I'd love to help you, but I need to go to bed.
But here's a quick guide.
Unfortuneately the picture is abit advanced, but pay attention to the FLAP SETTINGS. That's one of the important things for a good approach.
Nevermind the other technical jibberish, wont serve you any good since the default 737 in FS is in no way realistic, and lacks lots of instruments found in a real 737.
Here's an ILS (instrument landing system) approach diagram for the 737

Got this picture from a friend of mine.
The flare should be about 4 to 6 degrees in pitch, more than that and the risk of tail strike is high.
Initiate the flare when the main gear is about 15 feet above ground level (AGL) and cut throttles to idle. Do not use pitch trim during the flare, that's a no no.
I hope it helped you a little bit buddy. You're always welcome to ask more!