Let's see if I can explain this;

A remote start switch would clip on too the large upper post in the picture the battery +,
the other connection would clip on too the smaller connector on the right.
When connected, with a good battery and connections, good solenoid, and good starter when the remote starter button is pushed the engine will crank.
This is doing the same thing as when people "jump a starter" with a screwdriver.
The engine crank and if possible start, as you have bypassed all the safety interlocks, so it needs to be used carefully.
As far as the stop solenoid You have to know how your tractor works, does it energize to open the fuel stop and run,
or is it one of the ones that energizes a solenoid to shut off the fuel and stop the engine.
Once that is known the options to bypass that begin.
If it is energize to run can it be over ridden and pulled into the run mode and held with a bungee cord or similar method.
If it's energize to stop and is getting a stop command when you don't desire it can it be disconnected. If disconnected can you physically over ride it to shutdown when needed.
All of this is dependent on the individual being competent to work on their own electrical system with out issues.
Also on the fuel solenoids this would involve being comfortable with and conscious enough to reach in next to a running engine and getting there hands in close proximity to moving engine parts that can and will grab ahold of unwary individuals and remove bits and pieces.
So there can be two steps involved, one using a switch to bypass safetys and get your engine to crank, and #two if necessary bypassing your engine stop solenoid.