first you should choose the language that you feel familiar with.
second Home page gives you the opprtunity to look for language partner or teachers...
click on the partner language tab to look for partner all over the world ( you can specify country, language,...)
add the partner that you think useful to you by sending an inviation
once the partner accept you, you can be friend, so you can collaborate and exchange.
last but not least you can also write a notebook so evevry memeber can read it and correct it if there is some mistakes