If youre a beginner, in my opinion, you should be a little more concerned with just getting comfortable being smacked around by someone at full contact - if they arent a tosser and know you are a beginner chances are they wont try to hurt you.
Get used to taking punches you aren't expecting, when you know he's on the attack, bob and weave, try to take into account where you are in the ring.
Dont concern yourself too much with counter punches, just roll with whatever the other guy throws at you, keeps moving and focus on the fundamentals
- work things off your jab and dont try to make counters happen, just take an opportunity if you see it
- trying combos you arent able to perform will not do you any good.
And if the other guys are more aggressive, get a bit of bloody mongrel!!!!