Not a video, but here's a great guide written by a community member for Splinterlands (mobile is on the bottom of the post) :
https://peakd.com/hive/@keychain/using-hive-keychain-to-play-on-splinterlands
Works the same way with PeakD or any other dApp that supports Keychain login.
Awesome thank you! Hopefully he can figure it out now!