@andybassdoyle basically the Talkbox has a speaker inside it which amplifies your instrument sound - be it guitar, keyboards, bass etc.
You plug one end of the plastic tube into the speaker hole and the other goes into your mouth. The idea is you mouth the words you want to “sing” while the instrument sound coming out of the tube acts as your “voice”. You don’t need to produce any vocal sound yourself. It takes practice! I’ll attach some videos below.