button to change the character @ actor (new character)

xanxus92

hello everyone.. i'm still new in this game development..
i just want to simple game like swing copter for my final year project, with some improvement

1. can someone teach me how to make a button that can change the character@actor?
2. the character only can unlock after you get the specific scores, such as 10,20, and 30.

if you have link video @ tutorial document..can you give me....
thank you...