Be sure that you understand the different usages of "to"
e.g. I am going to visit my friend ("to" is part of the infinitive verb "to visit")
e.g. I am going to Brazil ("to" is a preposition of movement)
Many verbs of motion (but not all) are followed by a "to" and an indirect object
e.g. go, run, travel, walk. You need to notice this when you learn a verb.
Sometimes the same verb is used also with a direct object
e.g. I ran to the end of the street (indirect). I ran a race (direct)