First time Kegger, quick question

I am going to keg my first ever batch of beer from a kit I bought from Morebeer.

I am a little confused with the purging process: I am planning on cleaning and sanitizing the keg before use... Then, for purging, do I do this BEFORE I fill with beer, or after, or both?

From what I have read, I am understanding to fill the keg with CO2 before it has beer in it, release, and do this again 2 or 3 more times.. Then, fill with beer? What I am not getting is how do I not introduce oxygen back into the keg when I pull off the top and rack into it? Do I then purge the headspace a few times, finally setting it to my serving pressure?

Thanks fellas

I think everyone I know does it differently. I personally just fill with as little air introduced as possible. Hook it up to co2 and purge. Then shake as hard as possible and purge again. I have great results, but I'm sure I'm doing it wrong according to the experts.

No need to purge multiple times before putting the beer in. If you want to purge with CO2 before filling, go ahead. CO2 is heavier than O2, so you shouldn't get much ambient air in the keg while you're filling the keg.

But once you've transferred all the beer into the keg, go ahead and do this again to purge the headspace - this is the point when you want to purge 2 or 3 times to make sure you've cleared all that head space.

Thank you guys

Just a quick note. If you have more than 5gal and you fill past the bottom of your gas post, when you go to purge, beer will spray out. Learned that the hard way and have learned to tip the keg while purging fat batches.

Thanks for the heads up. Well, won't be kegging today like I planed. My dang racking came has a leak somewhere so I'm pulling up lots of bubbles on my test run! Luckily I was smart enough to do a dry run first. Argghhhh!!

I always get bubbles where my tubing slides onto the racking cane/ autosiphon. To remedy, I just put a twist-tie around the tubing, and tighten the crap out of it. One of these days I'll get high-tech and use a worm clamp. (I sometimes have to re-tighten the twist-tie, and it's a PITA)

Purging the empty keg seems like a waste of CO2 to me. Just purge the headspace after.