Hi Adrien!

Documentation is pretty good. The callsign you validate dictates the mode
you're authorising. If you want to use the single user mode, validate your
callsign. 

The FAQs on the site will answer most questions. If something is unclear
there, ask here and someone can give you clarifications. Have recently gone
through it myself and it is all accessible and straight forward.

A good place to start is by using the Echolink test server. That will
confirm for you if you have your audio set up properly. Press control o then
tab to the field for node number and put in 9999, then press enter. The test
server will explain itself.

Try to make a transmition and see if you hear it repeted back to you. If you
do, press alt d to disconnect. Now you're ready to connect to other stations
and enjoy it. Hope this helps.

 73,
Dave