The team will reach the hometown of the Guado, Guadosalam, after trekking through the pathways near the Moonflow. They will meet up with Tromell Guado at the entrance who will ask them to go to Maester Seymour’s manor.
Before you do though you will get a quick explanation of how to customize equipment from Rikku. The basics of equipment customization is that you can use items to fill in any empty ability slots on weapons or armor that you have.
Check out the Weapon and Armor Customization page in the Tips and Tricks subsection for more details.
The first door in front of you leads to the Guadosalam Inn. You can rest and save your game at the Save Sphere here.
To the right of the entrance to Seymour’s Manor is a treasure chest that contains a 
Mega-Potion.
Enter the doorway to the house on the far left side of Guadosalam to find 
Al Bhed Primer (Vol. XIII) laying on the ground as well as a treasure chest at the back of the room that contains 3,000 gil.
Head south from this house to find two people talking near a lamp post. There is a treasure chest near them that contains an 
Elixir.
There is a doorway in the center of Guadosalam that leads to the Guadosalam Shop. Inside you will find O’aka XXIII who is selling a host of brand new items, weapons and armor. You can chat with him as well and he will bad mouth the Guados for a bit before offering to sell you items again.
You can now go inside Seymour’s Mansion which is the large red door at the back of Guadosalam next to the treasure chest with the Mega-Potion that you picked up.
On the second floor you will find a treasure chest that contains two Hi-Potions hidden behind the balcony. Use the screenshot below to help you locate it.
Talk to all of the people in the main room of the mansion to continue the story. Try to enter the door on the bottom floor afterwards and Tromell will let your team in to the next area.
Tromell Guado will leave again. Take this opportunity to speak to all of your party members one more time.
Maester Seymour will join the party in the Great Hall where he will show the team images from around Spira, including Zanarkand as it was 1,000 years ago. He will also reveal his true reasons for inviting them in to his mansion. He will ask for Yuna’s hand in marriage.
Once you are back in control of Tidus in the Mansion Entrance, go just outside of Maester Seymour’s mansion to meet up with the team once again. Yuna will decide that she needs to head to the Farplane.
The entrance to the Farplane can be found on the top-most level of Guadosalam. Follow the pathway along to meet up with your team again.
Search the area on the left side of the screen for a treasure chest. Open it to obtain eight 
Lightning Marbles. Move ahead through the hallway and follow the path through to the Farplane. Walk up to the team for some additional dialogue.
Tidus will ask about the Farplane. Wakka will tell Tidus will understand once he gets there. Walk in to the Farplane once you’re back in control of Tidus. Rikku will explain that ghosts that appear in the Farplane are just Pyreflies reacting to the memories that each of them has of their loved ones. Leave Auron and Rikku behind and head inside.
Talk to Lulu and Wakka for a few short cutscenes. Wakka will have a conversation with his lost brother, Chappu, asking how things are going, etc. Speak to Lulu and she will talk about Wakka and Chappu. Tidus will learn that Lulu and Chappu used to be a thing before Chappu was killed. Head over and speak to Yuna to continue the story.
Yuna will tell Tidus about her decision regarding Seymour’s proposal. Tidus will attempt to make Jecht appear but he won’t, which indicates that he is still alive somewhere in Spira. Tidus will explain why he hates his father: his mother would ignore him whenever his father, Jecht, was around.
The 
Brotherhood weapon that Wakka had previously given to Tidus now contains a few additional abilities including:
Strength +10%
Waterstrike
Sensor
It is now a fantastic weapon to use. Equip Tidus with it before you continue. Make sure that you have obtained the hidden chest on the pathway to the Farplane that contains eight Lightning Marbles. Use the mini-map on the screenshot above to help you locate it.
You can use the Lightning Marbles to add Lightningproof to some of your equipment which will come in really handy for the next portion of the game (the Thunder Plains). Go back to Maester Seymour’s Mansion to continue the story.
Tidus will have a conversation with Lulu. Afterwards, talk to each of your party members while Yuna is meeting with Maester Seymour. Follow Lulu and speak to her again. Find Rikku and speak to her next. She can be found hanging off the balcony.
Talk to Lulu one more time. She will tell Tidus not to fall in love with Yuna and there will be three options given to continue:
This does impact cutscenes that occur later on. The character with the highest affection value will partake in certain scenes later on in the game. It does not have that much of an impact though on overall gameplay so choose whichever option you would like.
Head over to the Shop to find Kimahri exiting. He will explain that the Guado Potions which are purchasable at the shop are “good”, which is definitely true. They are not actually referred to as a “Guado Potion” though when you go to buy them in the shop.
Buying Potions is not necessary however you may want to consider buying some of the “Yellow” armor for sale in the shop. This includes the:
Yellow Shield
Yellow Ring
Yellow Armguard
Yellow Bangle
Yellow Armlet
Yellow Bracer, and
Yellow Targe
These items have the Lightning Ward ability which will be very helpful in the next area (the Thunder Plains). You may want to hold off on purchasing a Yellow Shield as you will receive a free one in the next area.
Walk down the ramp near the entry way to Guadosalam and you will run into Shelinda. Shelinda will explain that Maester Seymour already left.
Go back up and meet up with the group outside of the Mansion. Talk to Lulu one more time once you’re ready to proceed to the next part of the story.
Now that Maester Seymour has left Guadosalam you can pick up the 
Venus Crest for Lulu’s Celestial Weapon, the 
Onion Knight. Travel back into the Farplane and you will find a treasure chest on the left side of the screen. Open it to receive the Crest.
After Yuna has rejoined the party you can head down the walkway towards the Thunder Plains.
