Location / places
I'm going to the shops.
She went to the bank, cinema and then the park.
I climbed to the top of the tower.
It's fifty more miles to Brighton.
'To' indications a direction of travel and / or the final destination(s).
Relationship to other people
She is married to Frank.
He is the assistant to the CEO.
Changing the state of something
It was smashed to pieces.
He burnt the pizza to a crisp.
The play reduced him to tears.
With this use an object or person goes from one state to another. In the first example the plate went from a normal plate and then was smashed (verb). This changed the state 'to pieces'.
Attached or link two items
I tied my dog to the pole.
This web page is linked to the home page.
The boat is roped to the dock.
My heart is tied to hers.
Here one object is linked to another object - either physically or metaphorically.