How can I add an overlay to this plugin?

Hello there.
I’m trying to add an overlay into a Nutscript plugin called “badair” but I can’t figure out how can I do that. I already tried to copy an plugin with a working overlay but it didn’t work either.
I’ve got the original version of badair which works perfectly and the way I wan’t. Theres an modified badair plugin made by someone else for another schema, which is free, but, its kinda buggy and not so good but does have an working overlay.

The plugin is a plugin that makes you able to create an radioactive zone and also creates a gas mask item that you can wear to avoid loosing health from that marked zone. As I said, I want to apply an overlay on Plugin 1 which is the original one.
So, the folder does have two .lua files: sh_plugin.lua and sh_mask.lua

Here’s the codes:
Plugin 1 that needs an overlay*

sh_plugin.lua:

items/sh_mask.lua:

Plugin 2 that does have an working overlay*

sh_plugin.lua:

items/sh_gasmask.lua:

I’ve tried to copy to Line 25 to 63 from sh_plugin.lua of Plugin 2 and add “char:setVar(“gasMask”, true)” on the function “equip” on the original sh_mask.lua from Plugin 1 but it didn’t work.
I might have done it wrong, well, I’m a beginner at LUA coding. I can fix some simple stuff but this one requires more knowledge. :confused:
It would be aweasome if someone could help me to do that so I can finally launch my new project on garry’s mod.
Thanks a lot.