If all you want to do is just have a decent list to start playing so you can learn, then that's simple. Just make sure you have the requirments (HQ/troop choices). So have a CCS, take two vet teams and stick one in the chimera with possibly some meltas (if you have them with melta's) and the other vet team can be your "gunline" (yes, it wont be much of a gun line but you can stick a few hvy weps in there and make them dangerous), use your sentinals as your flankers, and that should get you started playing. More importantly, it'll get you started learning. Then when you feel comfortable, you'll be able to trim the list to what you want it to be. What suits your style of play. Another good thing to do is to read through the list's posted in this IG forum. That'll be a great way for you to see how others are building their army's.