polaris sportsman 6x6, chain tension??

Hello, any help would be great, 2001 sportsman 6x6 rear chain broke ( to the last axle), wondering if anyone knows how to add tension to the chain (new one), when new chain attached it very sloppy had to take 2 links out but still to loose.., any help would be great.

Was the original chain tight? No experience with these, so that is why I am asking.

Also, since the original one broke, is there any reason why it might have broke? In other words, is everything straight? If you have a lot of play in the new chain, it is possible something may have gotten knocked out of line. Just something to keep in mind.