New to cacti and succulents

I knew I'd be lucky and find some info here!
We have a flat near Livorno, Italy, and as we are only there for a few weeks every year, I decided to start cultivating cacti. (Having said this, we then had three spectacular thunderstorms last week!!) So I need to learn everything I can, as I have never done this before.

 

Do you have an open patio to grow them on??

They like a well drained, open mix.