Right
Well first you need to remember that Vatsim is not just another MP server. It is taken rather seriously and they expect you to have some idea of how to flightplan and of RT.
By flightplan i mean if flying IFR then you need to know how to plan a flight from say EGNX to EGPD which would read something like TNT1N UN605 POL N605 TALLA GRIPE DCT ABD.
You also need to fly with real world weather.
Everything is done as close to real world as possible and like in the real world if someone with no idea was to get in a 747 and go flying about then somebody would get pretty annoyed

The best way to start is to go to the website go to your division website mine is UK and click on the new pilots link. Study the information and I mean study

I know you will be keen to get online asap but if you dont do the above you will soon lose the enjoyment.
Then go to a small airfield and learn to fly VFR in a C172, learn the circuits. When you can, go to a manned airfield with TWR somewhere small not Heathrow or Manchester and start with the atc.
Whilst you can fly vatsim with only FS and Squawkbox3 there is some other software mostly free that will help. Links to most of these are on Vatsim somewhere.
Servinfo - very useful lets you see who is online atc and pilots, read there flightplans, get the weather anywhere etc. If you are in UK, get UKroute it is a vital aid to flightplanning within UK or UK to Europea destinations. And possibly the best of all you could do with FSNavigator, really helpful aid to navigation and flightplanning but I think that one is shareware.
Oh and yes, you can text only. Have you joined Vatsim?, you should have a Vatsim i.d. and password you need to enter that in SB to get in.
Read the website theres lots of useful info on how to connect etc. Server ip's and so on.
Good Luck