It's not that hard (at least IMO), specially after watching the video. What I did was basically the same thing what is shown on the video, which is:
1- Turn ON the system but do NOT turn On the Transmitter but you can raise the antenna thou (this will spare you a second of two later on). Don't forget about this, if I'm not mistaken if you turn on the Transmitter the incoming F-117s will detect your battery's aproximate position and will avoid it, making it impossible to shoot at them.
2- Set the elevation (height) to 8km
3- Watch the search radar (P-15 "Flat Face") and set it's the scanning to the minimum (90Km) - If I'm not mistaken the F-117 can only be detected by the SA-3 SNR at distances lower than 20Km (above 20km the F-117 probably won't appear in the SNR but will appear on the search radar).
4- Place the range dial/line at 15km.
5- The first incoming F-117 won't aproach to less than 20Km from your SAM battery so it's most likelly that this F-117 can NOT be shot down by the player's SAM battery. BUT, a second F-117 which comes from the south will pass near your SAM battery (15km or even less).
6- When this second F-117 is at a range of 15Km (aprox) turn the SNR towards the target's estimated azimuth and only then now will you turn ON the SNR transmitter!
6- Make corrections if necessary so that the F-117 will show on the azimuth display (X - button console).
7- Make corrections in the elevation, azimuth and range console (A - button) so that the target will stay on boresight and mark the target in both indicators (left and right).
IMPORTANT NOTE: Note that the F-117 is a stealth aircraft, which means that the F-117 "target blip" in the indicators is much smaller than a conventional aircraft "target blip" (like for example an F-15). This means that you have to look more carefully into the 2 displays (in the A - button console) in order to find (and place in the boresight) the F-117 "target blip".


I also advise you to train more (in the live firing range) in the SA-3. In terms of marking targtes this SAM system (SA-3) works considerably diferent than in the SA-2E or SA-2F and IMO, the SA-3 is a bit more confusing regarding target marking/tracking than in the SA-2 (both -E and -F)


I hope this helps you somehow...