Could someone explain something I am having trouble with, it's about this election?

It’s two things really Trump keeps saying if Clinton wins the election is rigged, but if he wins it is not? HUH?

Now for the Trump supporters they keep screaming Clinton is a liar, liar, liar and Trump isn’t?
All you have to do is listen to him for just a few minutes and he spouts at least half a dozen in that short time, so why isn’t he a liar as well?
Please make it simple I am just a dumb Canadian looking in with utter amazement.