Despite not having experience with text corrections. I believe I might help a little bit.
Conexão Mundo 2014, I had the opportunity to live an amazing experience, meet new people, learning a new language with my schoolmates have been wonderful, have so much fun in our Hangouts, play guitar and play games is amazing.
Small suggestions in order to improve your text: Through
Conexão Mundo 2014 I had the opportunity to live an amazing experience such as meeting
new people. Learning a new language with my schoolmates (or classmates if they're in the same class as you) have been (use "was" instead of have been if it's over) wonderful. I had a lot of
our Hangouts; playing guitar and playing games was
amazing. (I used "was" in this last sentence since it is a past action).
That's all I can do. I'm sure there will be others that might offer some help as well.