I am pretty new to the game & was thinking of running a Necro Pet build. I was wondering if their are any links I can go to, or if anybody can advise how I should make the loot filter look like so I get the kinda gear I want for my necro.
Welcome to the forum. 
The easiest would be to tick the pet bonuses and My Masteries boxes in the loot filter in addition to the ones ticked by default. But if you’re new to the game I personally wouldn’t block seeing other items since you need to build up your iron reserves for when you want to buy items, buy back points at the Spirit Guide, etc.