Hey guys, i'm trying to build a talkbox, and stuff says to connect it to the speaker output of my amp... i'm confused on what this means though

i have a crappy Ibanez SS 15 watt amp, Marshall MG 30 watt, and an Orange TT.

i want to use it with one of my crappy amps, but what is the speaker output? It's not the headphone out, so i'm confused. Do i connect it to the leads where the speaker connects? HELP
My Guitars:
Gibson Les Paul Studio
Epiphone AJ
Ibanez Strat Copy

Orange Tiny Terror Head
Old beaten up Peavey cab
Marshall MG30DFX
Those little combo amps wont have a speaker out jack they are going to be hardwired to the amp internally. If you need a jack you will have to add one.