Alder will want to start training in Floccesy Town until he notices that you have two Town Maps. He tells you to look for Hugh in Route 20.
In Route 20, you will find some Pokémon Trainers who want to battle you. As soon as they make eye contact with you, they will battle you.
The kid near the bridge wearing a red hat will challenge you. He is Youngster Terrell and he has a level 4 Patrat.
Farther east, Lass Isabel will challenge you. She has a level 4 Purrloin.
If you go north from Isabel, you find a Parlyz Heal in the grass.
North from there, Youngster Petey challenges you, sending out a level 4 Patrat.
Farther north, there is a hiker, but he won't challenge you. He will tell you not to go farther east until you get a gym badge.
Go north from the hiker and check on the rock on the left. You will find a pokéball!
Now go west and continue up the path to the north. You will find yourself in Floccesy Ranch.