There are 2 ways you can access the commands:
Entering the correct key combination will directly fire the command without going through MonKey's interface.
However, in some cases you will be required to enter some parameters for the command, in which case MonKey will open the Parametric Command Panel.
Example: Hitting CTRL+T will open "Find Asset", which requires you to enter an asset name.
To Execute a command by name, simply input as many key words as you want to find the command by name or quick-name, and select the command you wish to use from the results. Click on the selected command, or press ENTER or TAB to execute the command.
If the command is parametric, you can either press CTRL+ENTER to execute it with its default parameters if available, or press ENTER or TAB to open the Parametric Command Tab.
Most commands support Undo so that you can revert the changes the command did.
However, certain operation cannot be undone due to Unity's limitation: most operations on assets cannot be undone (renaming, creating or deleting).