Help layers on every slide

Hi everyone, 

I'm building a set of courses, and I want every slide to have an icon in the upper left corner that after clicking shows a layer with help.

I will have three types of help layers: one that explains navigation for the speech bubbles, one with a freeform quiz instruction, and one more with another instruction. 

I have two issues:
- I've been adding layers manually to every slide, adding triggers to show and hide help layers. Any solution to make it faster? Will Master Slide layer work?
- I had to change the instructions on every layer due to some last-minute changes in the project. Is there any chance I could insert an <instruction> block that I can later rewrite, and it will automatically change on every help layer? 

Hope I managed to explain myself well :)