Can´t find it 
After beating the Elite 4 and helping the Koril Town science club, take the subway in Suntouched City.
Ok got it thank you
how do you help the scientists? i cant find out how
This post is 6 months old, but I’ll help anyway. Just saying, you probably should have made a new thread and quoted/linked this one.
The scientist in the back will offer you a job. Talking to them again will transport you to a special room overrun with fossil mons. Defeat the kabutops in the back and you can go on your merry way.
ok thank you im new to this so thx for the tip
I defeat the Elite Four and the Subway sad i cant get in
You have to defeat the timeless in the crystal caves as well.