This one is easy,,, Actually these two are easy
IF your cord is detachable, Work on the inlet, forget the cord work on the inlet
If the cord is hard wired.. Get the proper pigtale from your dealer or camping world (Either 30 or fifty amp replace the existing cord with the pigtail.
Also get a matching OUTLET and box. Replace On the cord replace the existing RV with the outlet and box (Basically turn the existing cord into an extension cord) It will work fine.
NOTE: if you have an "Inlet" you remove the wires from the inlet.
Put a proper size plug on them and plug into the Powwer monitor.
THis time you use a pigtail with a FEMALE oulet hooked to the inlet
IN both cases you get
Existing cord------(Optional inlet)--Guardian---RV
If Money is no object... A Hughes Autoformer Install kit contains everything you need to do this job. Bit pricy, but it's all in the box.