schneider m218 controller

Hi, everyone
I am new to schneider PLC, I used to program Omron and Allen Bradley like 25+ years ago
things have changed a huge amount since then as you know.
So I have a M218 controller, I need to change this controller in the field!
How do I connect to the existing M218 controller and retrieve the program/upload
to my laptop?
I have Somachine 4.3 and have tried to run a small program, but it will not execute,
I can connect online it downloads and says it's running, but nothing changes if I give input
there is no output? What am I missing?
can anyone assist with this???