Painting an exterior Fiberglass Door

I just purchased a white Fiberglass exterior door (Benchmark by Therma-True), my question is about paining it. They wanted $500 to paint the door so I decided on painting it myself.

Here are my questions:
1. Do I install the door first and then paint it?
2. Should i install the door and the take the door off to paint it?
3. Any Paint company or type recommendations?
4. any tip or tricks I should be aware of?

Thanks guys

Most primers cover all sorts of materials these days.
I Recommend Ben. Moores "Fresh Start Acrylic" Know that they have two different fresh starts now. One for there top LOW AND NO Voc paints and one for there still high quality regal line of paints. Make sure you get the right one for your finish coat.
First, lightly sand and prime the top and bottom edges of the door. These are typically not painted, but can save the life of the door if exposed to moisture which is usually the case with exterior doors.

Yes, hang the door first, because you are going to scratch it while hanging it otherwise. I recommend old hinges then replace them with the new hinges after painting, because you will inevitably get paint on the hardware. Hang the handle and dead bolt if an exterior door to ensure everything lines up and works. Then take the hardware of to paint it. Leave the hinges on so the door will swing.

Lightly sand all surfaces of the doors and casings. 120 - 180 grit. 180 is best.

Start with the door closed and prime the side where you can see the hinges. Prime everything you can see, door and casing. Skip the window You can tape it of if not able to control the brush.
Prime the edges and then swing the door open

Second: Check for runs on the other side of the door before they dry on you and paint the remaining door casing inside and out.

Third: prime the other side of the door and the check the first side for any runs again. Runs show up on the edges.

4th: Once the primer dries, putty all nail holes in the casings and lightly sand again.

5th. Caulk all gapes for air seal and aesthetics. Once caulk dries. Use quick dry caulk. I like bolt. 2-3hrs minimum, the apply two finish coats in the same order.

on the thermal-true website they say to stain the door, does that make sense?

So i got oil Based paint for my door, how many coat's are needed? The guy at the store said to put one coat on, sand it, then put the second coat on. Thoughts?

Two coats are required to limit chips or peals. Make sure the door is FULLY DRIED before rehanging it. The paint will pull off at the jambs if it is not dry, making you touch up the edges again.

After the priming coat has dried the next step is to paint the door in one coat of undercoat. Make sure you use a good quality brush when painting your door. I recommend American brands such as Purdy or Wooster. The synthetic brushes also seem to hold more paint than traditional brushes, saving you time dipping in and out of the paint pot.