Best way is to first download Unren@
You must be registered to see the links
Then that should in most games create a console and creators console (If it does not you need to edit the files in the renpy/common directory 00console.rpy and 00library.rpy changing console to True from False using notepad ++)
Then in some renply not all in the game folder there is a script.rpy this unless mixed coded has all the console commands for variables in it
It can be read changed using something like Notepad ++ unless it has mixed or protected code (few have though)
You can use the online one it will allow you to edit variables but knowing the variable that you need to edit may be the problem and it is limited to daily use maxes
I dont speak English or write it well so ignore my mistakes I do