Let, lets or maybe let's...?

[oboeteru]

I don't have any idea what is the difference between these three and when I can use them. (btw, here new question appeared :P Can I say: 'what are THE differences?' or is it reserved just for singular?)

I mean phrases like down here:

Let me go.
Lets stay here. (Wouldn't it be rather: he lets me stay here as normal Present Simple?)
Let's dance.

If I wanted to say to someone to chill out and to not hurry, should I say:
'so let not force anything for a while' or it's incorrect?

[bhaisahab]

I don't have any idea what is the difference between these three and when I can use them. (btw, here new question appeared :P Can I say: 'what are THE differences?' or is it reserved just for singular?) "What are the differences" is OK.

I mean phrases like down here:

Let me go. This is fine.
Lets stay here. (Wouldn't it be rather: he lets me stay here as normal Present Simple?) This is incorrect. "Let's (let us) stay here" is correct. "He lets me stay here" has a completely different meaning.
Let's dance. This is correct.

If I wanted to say to someone to chill out and to not hurry, should I say:
'so let's not force anything for a while' or it's incorrect?

Bhai.