In order to install the Plenty Markets IMN Module through github the first thing you need is the url to the github repository you can find it in the following link
Once you have the url you have to make sure you have an account on github, if you don't you can create one through the following link
Now go to your Plenty Markets store admin panel and click on Plugins -> GIT
Click on the "+" button to add a git repository.
Add the github repository url, your username and where it says token your password, master branch is correct. Then save.
Once you have done this you can now build the module. You have to go to Plugins -> Plugin overview
Then unselect the checkbox Not installed and click on the search button.
You should now see the IMN module, you can install it and active it, then click on the save button to build it.