How much cardio? if any?

I was wondering I want to put on some mass in the next couple of months. I will be taking AS. Can I still do a little bit of cardio? Or is it totaly out of the question. I'm a pretty big guy 6'3" 278lbs.
I'm basicly trying to get stronger and then slim down at the end of my mass building cycle. Should I wait on the cardio till I'm done or can I still do some now? Thanks

try not to go over 70% of your max heart rate for an extended period of time. go around 65% max for 30-50 minutes eod.