The infinitive with ‘to‘ is used to talk about people’s purposes, the reasons why they do things.
Sara is going to the shop to buy a new CD.
(= because she wants to buy a new CD)
I’m going to Africa to have a vacation.
(= because I want to have a vacation)
DO NOT USE “for” before the infinitive of purpose!
Sara is going to the shop for to buy a new CD. *
I’m going to Africa for to have a vacation. *
