Usage of "not".

Hi, guys.

I'm really confused about how to make some kind of sentences, but the hardest to me is the below.

Look what I firstly wrote " I lied to don't go swimming with him, and now I have to keep my lie to don't give embarrassing explanations"

I thought it was fine, but I asked a friend anyway. And then he said that part of that sentence doesn't make sense. Like the "lied to don't...", I thought when I used "don't" I was referring to myself, like I used don't, because I didn't want to go swimming.
Then, I asked for a help and how he'd write that sentence and then he wrote, " I lied so I didn't have to go swimming with him and now I have to keep my lie to not make embarrassing explanations"

Now, I'm trying to get some logic from his sentence and trying to make my own, how about this "I lied to not go swimming and now I've to keep my lie to avoid giving embarrassing explanations"? I

I'm not sure about the usage of "not" lonely. Can anyone give me an explanation or a link where I could learn about it, please? I've been trying finding it on google, but I did not find.