I bought the puma ultra 1.1 but the show is stiff

Hey guys so i bought the soccer boot and started training everything felt decently

I went to train in them and the sole felt so stiff the upper felt different and kinda weird tbh

I tried it on in the store and thought maybe its because these are stones here they feel stiff so on ag its not an problem....

How do i make the sole not stiff anymore and how does the boot feel comfortable?