As Spikey mentioned, most of the left and right clicks have been swapped (by default).
So to add edges it is CTRL and Right Click – just make sure you are in edit mode (which I’m sure you are)
But the modifiers work exactly the same in 2.8 as all the older versions.
Just post a specific question you are having troubles with and we can help.
I will say that using a mouse will be much easier than using the track pad.
