It’s very confusing for foreign speakers because many English people use the verb ‘to lay’ instead of the verb ‘to lie’.
To lie (verb): (1) to be horizontal on a bed or floor, e.g. I was lying in bed; I lie on the floor when I do exercise.
Past tense of ‘lie’ is (unfortunately) ‘lay’. e.g. I lay on the bed yesterday. Present perfect: I have lain on the bed for hours. (This is not often used these days though.)
To lie (verb): (2) to tell an untruth. Past tense: ‘lied’. I lied when I told you I had gone to London.
To lay (verb):
(1) to put something down. e.g. I decided to lay the flowers down on the ground.
(2) To set a table: Would you please lay the table (put the knives and forks on the table)?
(3) To lay an egg – what a chicken does.
(4) To lay a woman – have sex with her.
(5) It can also mean the same as ‘to lie’ e.g. I want to lay down on the bed.
Past tense: ‘laid’. e.g. I laid the table yesterday, I gently laid the flowers on the ground.
Present perfect: I have laid the sheets out in the garden.