Verbs in infinitive form

I am confused when to use "a" before a verb in its infinitive form. For example 

Andiamo a vedere = Shall we go to see....

Vado in farmacia a prendere = Shall I go to the pharmacy to get...

Vuoi andare = Do you want to go 

Vuoi provare = Do you want to try

Thanks

 

This is in lesson 8.8 .  They have a few guidelines, but generally recommend memorizing the preposition with the verb.

Andare "a"
Provare "a"

I am having the same issue, I didn't really understand the explanation!

Ciao a tutti,

in Italian as well as in English there are some verbs that you will need to memorize.
In Italian in fact some verbs are followed by the preposition "A" and the infinitive verbs as:

Andiamo a vedere = Let's go to see....

"Andiamo" is a verb used as "let's go" . You can combine with other verbs as
Andiamo a giocare
Andiamo a mangiare
etc., etc.

Vado in farmacia a prendere = I go to the pharmacy to get...
In this case the preposition "a" is used as in English "to"
(to get=a prendere)

Vuoi andare = Do you want to go 
Vuoi provare = Do you want to try

'Vuoi" is a modal verb which means "you want" or "do you want" in a question.
For this reason the second verb will be an infinitive verb without the preposition.

I hope this helps.