It can be daunting when doing sewa, but best keep a little 'dar' in your mind, then you make less mistakes. The more confident you become the more likely you go into hunkaar and make mistakes.
As long as your hands are clean then parna is not required, however if you feel you want to use parna then all well and good.
If the chaur touches your clothing this is not cause for concern but I would hold the chaure with one hand and let the handle of the chaure Sahib rest on your other forearm and let the hair drape over, then when actually doing the chaure hold with both hands and swipe high over Guru Sahib Ji a few times mabe reciting "waheguru" in your mind.
Dhan GuruNanakDev Ji Dhan GuruGobindSingh Ji Dhan GuruGranthSahib Ji Dhan DasamGranthSahib Ji