Go to the lab to talk to Professor Rowan; he’ll give you Pokedex and your main quest: fill it with by capturing and discovering as many pokemon as possible
Go south on Route 219 to get the Antidote in the sand
Go back home on Route 201 to talk to mom, who will give the player a guidebook to help them whenever they are stuck
The Rival’s mom will give the player a parcel to give to the rival when the player sees them in Jubilife City
Go onto Route 202, where Dawn/Lucas will give the player a tutorial on how to catch the pokemon and 20x pokeballs
Catch a few pokemon for a selection;
Bidoof (grass)
Kriketot (morning/night)
Shinx (grass)
Starly (grass)
Collect potion from the far left of the left grass patch