“Lie” and “lay” may be the most confusing words in the world for writers. As an editor, I see the confusion all the time. I even double check myself sometimes! I hate these words but there’s no way around it.
Here’s how I get it right: I use a chart!
I Want to say
|To rest/recline||lie||is lying/they are lying
Jack is lying in the cot.
The cows are lying in the field.
|lay or has/have lain
Yesterday, I lay in bed with a migraine.
He shouldn’t have lain in bed that long.
|To put or place down||lay||is laying/they are laying
I’m laying this mug on the counter and leaving.
C’mon, they’re laying the pizzas down!
She laid the book down.
|To be dishonest||lie||is lying/they are lying
Jack is lying about where he’s been.
They’re lying about who was there.
After I paid, I learned that he lied.
It’s really confusing. I apologize on behalf of the English language.