The grammar is explained in the textbook like this:
"let + 人 + base form of verb" means "to allow a person to do something" and
"help + 人 + base form of verb" means "to help a person to do something"
This post is almost exactly the same as my previous post for this game (it works for both grammar points) so please refer to that for more details - see link.
The ‘questions’ I entered have three prompt words such as these, Dad + me + chess. The students have to make a sentence from them like this depending on which of the two targets are in play:
"Dad let me play chess." or "Dad helped me play chess."
Each round students will use either 'let' or 'help' as labelled in the PowerPoint.
The PowerPoint is from taysteachingtoolkit.com and the rules and gameplay are described in the notes in the slides. Search there for Pi-Gru if you need more information.