After you go through Santalune Forest and Ouvert Way, you reach Santalune City, where you can find the first pokémon Gym in Kalos.
The Pokémon Center is just north of where you enter Santalune City. Go inside. Tierno tells you what you can do at the Pokémon Center. Talk to the nurse to get your pokémon healed up.
You can use the computer to the right of the nurse's desk to access the PC. This is where the pokémon that you catch are sent if your party is full. You can use PCs to change the pokémon that are in your active party.
Behind the nurse's desk to the left, there is a fitting room. Here you can change clothes. You don't have very many different clothing items to choose from yet, but you can come back later when you get more clothes.
Behind the nurse's desk to the right, there is a Poké Mart. Be sure to buy Poké Balls and healing items if you need them.
Outside of the Pokémon Center and to the right, there is a clothing store. They sell a selection of hats and accessories.
To the west of the Pokémon Center, a girl in one of the houses will tell you how your relationship is with the lead pokémon in your party.
North of the Pokémon Center, east of the fountain, a boy in a house will give you a Great Ball, which has a higher chance of catching a wild pokémon than a Poké Ball.
West of the fountain, a Hiker in a house will give you a Farfetch'd (nickname: Quacklin') in exchange for a Bunnelby. The PC will open, so you can do the trade even if you have a Bunnelby that is not in your party right now.
North of the fountain, there is the Trainers' School. Talk to the white-haired guy near the entrance to get three X Attacks and three X Defenses.
To the west of the Trainers' School, you find the sister of the Santalune City Gym leader. West of her, go up some stairs and check on the flowers in front of the house. You will find a hidden Super Potion.
To the east of the Trainers' School, there is the Santalune City Gym. Go there to meet a roller skater. She challenges you to a pokémon battle, and if you win, she'll give you your very own pair of Roller Skates.
Roller Skater Rinka has a level a level 7 Zigzagoon.
After the battle, Rinka gives you a pair of Roller Skates. When you move around using the Circle Pad, the Roller Skates will automatically snap onto your shoes and you will skate around. To walk around, use the +Pad.
After battling Rinka and getting your Roller Skates, go into the Santalune City Gym.