The word "too" has also other meanings.
It is also used in combination with adjectives.
Here you have some differences between "to" and "too":
He is too fast and too furious.
I like your song too.
I like to play.
In order not to lose too many friends, I will stop hanging around this girl.
It's too late now, I'm going to sleep.
We have too much water, what should we do to get rid of it?
As you can see, in all my examples "to" belongs to a verb.
Too is used to increase (not sure if increase is the best word now) adjectives.
Edit
When must I use to or too?
It's also better (it's not wrong if you don't do it) to use some markings, as I did with
to and
too.
**Neither a teacher nor a native speaker.**
Cheers!