Use the gold coils on the goldfields. Start with factory presets. If it's noisy try dropping the threshold setting a notch or 2. Then look at the sensitivity, if the detector is running quiet, try bumping 1 or 2 digits, if noisy drop it down.
I find for a beginner the best thing is to get the detector running smooth ( as against warbling) and reasonably quiet. Also unlike the GPX5000 I have with a speaker next to my ear the X terra speaker is near your hand and difficult to hear, so headphone use is a must.
I have the 705 Goldpack with the Concentric 7.5kHz coil and the 6" elliptical DD 18.75kHz. I've used it mainly at the beach with the concentric, but I'll be going to the GT in a few weeks for a month, so I'll give it a bit of a gowith the DDs on the mullock heaps using the 6" mainly for small stuff.
Another thing is use fixed GB with the DDs, but ground balance often. It's possible to track out small stuff if you use tracking mode. At least until more experienced.
I guess my advantage is that if I have no success in short order with the 705, I can go back to my 5000........
Added by edit......Get some small lead shot, air test the detector to begin with and adjust settings a bit to get the best response. Then dig a hole and bury the shot at various depths to see what happens. (put the shot in a 2" square bit of duct tape folded over when burying it makes it easier to retrieve) Doing this may help your confidence in the detector working as you want it too.