This engine works with the Hill Climb Racing Microsoft Store version.
"Processes -} HillClimbRacing.exe"
Then simply double-click on the value box and enter your desired amount.
I did it like this : 99,999,999 coins - 99,999 diamonds
But don't overdo it, otherwise you will slip into the red, should that happen just enter a "0" again and try again.
How to use this cheat table?
Install Cheat Engine
Double-click the .CT file in order to open it.
Click the PC icon in Cheat Engine in order to select the game process.
Keep the list.
Activate the trainer options by checking boxes or setting values from 0 to 1