Kangoo wont start

hi all.

My Renault kangoo van will not start,the battery is o.k. (new 2 years ago and I tested it the other day) but drains over night, even when it does crank it will not fire up, ive tested my glow plugs and these are all o.k., all reading less than 1 ohm, ive noticed a lot of air in my fuel line but unsure how to get rid of this and also I want to test my starter motor but unsure of its location.It is a Renault kangoo 1.5 2004.

Thanks all.