This is the sentence I made which undoubtedly looks wordy in my opinion.
A: No, that's wrong! Be careful with the fire! You're going to burn them all!
B: Do it right know then! Don't just talk too much without doing anything.
I hope you get the situation. I need to substitute the terms in bold with a single word or an idiom, is there any?
If the intent is to show frustration with the person talking so much, this expression or similar fit:
Get out and push, or shut up.
This refers to a situation where someone sitting in a car is yelling corrective instructions to someone pushing that car.
The closest expressions I can think of that match those words are:
If you're so smart, ...
If you know so much, ...
If you can do it better, ...
and
... why don't you do it?
... come and do it yourself!
Another common phrase to describe this is all talk and no actiion. For example:
Do it right now then, unless you're all talk and no action.
