Usually the scanner picks up a lot of stuff, when leaving the ship. Sent the ship away to minimize distortion.
Look at your wave scanner, at best drive a slow circle and look from where the most signals are coming in. Go in that direction and keep your eyes on the wave scanner. The signals, usually broad distorted fields on your scanner, will start to narrow down and the sound these signals make will become more distinctive. The signals will continue to get smaller but increase their sound and visual intensity on the scanner. Once the signal is only a centimeter wide (depending on the monitor of course) and only giving a short but intensive sound impulse, you should get a contact on your terrain scanner, just like the contacts you are used to, when flying in space. Change scanner range and continue to slowly follow the signal. If it suddenly disappears, you have driven past the object. The rock you seek will stand out from the other rocks, in form, size and / or color. Like said in the above post, the diamond shaped target indicator will pop up over that rock and you can then target it.
I know, i have posted in one of your other threads, seeking for help on this topic. I am currently exploring 2000 lightyears far out... if you care for a little exploring, feel free to send a friends request and we meet somewhere half way and do a landing operation or two, where you can get some practice. My commander name is in my signature.