How can I say?
I'm working at a cafe.
Then, I want to say like that.

"Your drink is ready at the counter."
"You can pick up your order over there."

Please correct my grammar, or if there are other expressions, please teach me.

Question

How can I say?
I'm working at a cafe.
Then, I want to say like that.

"Your drink is ready at the counter."
"You can pick up your order over there."

Please correct my grammar, or if there are other expressions, please teach me.

Answer

Both of those are fine. 
You can also say "You can pick up your order at the counter.", which is more precise than 'over there'. :)

Answer

First line is fine .   For second line you can say: You can pick your order from the counter.

Answer

You don't have to say the second sentence the first one should explain enough where the drink is that.