Correct "Select all" pattern

I'm developing a material design based desktop app where I encountered some UX problem and can't decide how to implement "Select all" capability.

Situation: I have the right side panel with a list:

There is an action to "Select all" by checking a checkbox "Resource name/Branch".

Problem: This UI is not really user-friendly. Need to think a better solution to implement action "Select all".

Questions: Maybe I should rename header name to "Select all"? Would it solve the problem? Or is there any other good alternative ways to make this design more user-friendly?