Making a /click variable

I’m a bit curious as to how the /click functionality works. I tried to find a thread already but all that pops up is clickrate/MS and that’s not what i’m after. Specifically, can you make a /click [mod:shift] WHATEVERMACROHERE to be cast while shift is held? I have tried a couple of macros with this functionality but that part has never worked so I’m just not sure if it’s something on my end or not. I can give the specific macro(s) I’m trying to use if that will help with anything.

Where you place that command in the action matters. The action is read from the top down. If you don’t have that line before the main command then it will never be evaluated. You will also need this in the same place on each action that you want this to occur. This is why people create variables and put the variable reference in each action.

Also the command needs extra information if you are using KeyDown rather than KeyUp. See MACRO click - Warcraft Wiki - Your wiki guide to the World of Warcraft and ActionButtonKeyDown or ActionButtonKeyUp and Why this matters Macro Cycling not firing · TimothyLuke/GSE-Advanced-Macro-Compiler Wiki · GitHub

Whole lotta information that I somehow missed, so ty!

Basically what I have now is the following:
/click [mod:shift,nochanneling] MMA-AUG-EBONMIGHT (in the main macro as its own variable at the bottom to call on the second macro.)

/cast [mod:shift,nochanneling:Fire Breath] Upheaval
/cast [mod:shift,nochanneling:Fire Breath] Upheaval (first block of the second macro)

I would then have to add the mod:shift,nochanneling part to every block in that macro right?

not necessarily - it depends on how you have written the second set to work however if that variable is at the bottom its never going to call the secondary macro.

Look at the compiled template. Your click command needs to appear in that before any /cast or /castsequence lines in the main actions