Microsoft offers a great site with the documentation of dotNET. And here you have the possibility to download this documentation as PDF. Look at the bottom left and you will find a link to do that.
Also, if you don’t have enough knowledge in English language, you can switch to the language of your choice and the actual article will translate to it machinally. Scroll down to the bottom of the side and you will find on the left a link to do that.
In this documentation you find a lot of excellent information about VB dotNET, so it could be much more easier for you to use VB dotNET inside UiPath Invoke Code activity.