Well, instruments are depend on your panel. Usually every panel have 2 main screens ND and FD or HSI and VSI. (alias Navigational Display, Flight Information Display, Horizontal Situation Indicator, Vertical Situation Indicator.
Preparations before an ILS/instrument landing is to setup the ILS frequency on your NAV1 radio, and the runway heading on your Course selector.
Normally an ILS glideslope have 3 degrees descending. It means, ATC will guide you to 2000 ft above ground, and approach will start about 7 nm far from runway. This is quite close. At this moment your gauges will already show you the centerline since 2-3 minutes.
ND: or more simply, the digital compass rose screen. On most panel you will se a purple/white needle in the center. This will show you the longitudinal center of the ILS virtual line. If it is absolutely centered you are on the right vector. Normally inbuilt ATC will guide you to intercept the ILS glide slope with a last 30 degrees turn. Before reaching the correct heading, the purple line will be stand on one side of the display. As you reach the correct vector, the purple line will move to the center. In this moment start turning toward the correct heading, and with luck, you will hit the correct vector toward the runway. Try to keep the needle in center, against crosswinds, and your heading will be right for landing.
FD: mostly the LEFT digital screen, that contains the altitude and speed gauge too. This screen usually have 2/3 purple diamonds. To be easy, these diamonds show the ideal centers of every aspect of the glide slope and you must move your plane so the diamonds are centered on their slides. 1st is existed (not always) on the left side, next to the speed gauge. If it is vertically centered, your airspeed is OK. If it moves up, your speed is low, if it moves down your speed is high. 2nd is existed on the right side next to the altitmeter slide. If it is centered, you are on the slope, if it moves down then you are above glide slope, if it moves up then you are below glide slope. 3rd is existed on the bottom. It is the same as the needle mentioned at the compass rose. It will move left if you are right of the centerline, and moves right if you are left of the centerline.
ILS diamonds/needles pop up only if you setted the ILS frequency correctly, and you are about 20 nm far from the touchdown point. Near the touchdown point (100-200 ft high) it is better to change to visual approach, because your diamonds can screw up everything

Safe landings

If you need more details, then you should really try the inbuilt flight trainer. The best excersice is to land a Cessna with ILS, in 0 visibility conditions
