4CH Channel Wireless RF Remote Control

Hi
I have a (Uno + 4 CH Relay Module and RF module) working fine between 2 Ardunio UNO's via RF,

On one end I would like to replace the 3 pieces with one but the new module has no instructions. It is a 4Channel RF module which usually gets Relay control via a small hand held 4 button remote like a car door unlock/starter.

What I have now and it works good.

What I want to replace it with which saves me the cost of an UNO and is smaller/simpler.

Because I don't have or want to use a button remote I want to simulate the button control using the remote UNO and RF. What code will send the same RF signal as the 4 buttons?

I bought the new module here. Thus the reason for no instructions.
link

Thanks for looking. I am sure someone else has already done this.

This thread that I found with a search for "rf relay Arduino" may help.

Thanks
That link has more information than the others I had found. I should be good to go.