Okay, I almost don't want to believe you that you've read all the text in that chapter. It must have explained where those endings come from, that's pretty essential... I'm going to give you a hint. Even though the English verb "bring" ends in "-g", sometimes we add "-s" to it...

Okay, maybe that's not fair. I'm almost tempted to get that book for myself, to follow along and give more relevant insight, but the money is pretty tight... Hindsight 20/20, I should have tried harder to persuade you to get a book that I already have, namely "German Demystified", but oh well...

So, if neither that hint suffices, nor the book explains it further, let me know, I'll do an explanation. That's a very basic piece of grammar, and I'm as confident in that as can be.