Two Team Yell Grunts will fight you in order to ensure a nearby Silicobra can sleep. Fight them and then they’ll get out of the way.
You’ll also be introduced to Opal, who will give you Opal’s League Card.
There are a lot of ladders for you to climb on the route and these will take you to various parts of the route. There’s one ladder near the beginning of the route that takes you to a fishing pond, and there’s another set of two ladders shortly after that. The second set is relatively irrelevant, but be especially mindful of ones after that.
If you want to progress on the route and make your way to Stow-on-Side, take the ladder on the right after fighting Backpacker Diane and her Sawk, then continue underneath the stone arches and keep following the path until you reach Stow-on-Side.
Otherwise, take the ladder to the left of Backpacker Diane and you’ll find a campsite as well as a researcher called Cara Liss, who will revive your fossils. She’ll need two fossils in order to revive a Pokémon — you’ll first need to give her either a Fossilized Bird or a Fossilized Fish, and then you’ll need to give her either a Fossilized Drake or a Fossilized Dino. The combination you give her determines which Pokémon will be revived: