Most people start from dr. Clark's LF'es, but you can pick up which one is more convenient for you. Just be not afraid, relax.
The worst thing can happen is a stone stuck in the narrow neck of your gallbladder or a stone could stuck in the tube of your pancreas since gallbladder and pancreas drain their fluids into the same tube that goes to the duodenum. In that case you either do yet another full flush with Epsom Salts or just drink two doses of Epsom Salts two hours apart as is described in Clark's LF. Definitely use Epsom Salts since they like nothing else relax everything they mange to get hands on.
I got stones stuck two times with just very mild pains and one stone was stuck in the pancreatic duct since it let me know with mild pain on the left side. In both cases I did another Liver-Flush and everything was just fine. The biggest stuck stone was 25mm size. And that was the worst case which is laughable.
I never did coke flush, I am fine with modified Clark's flush. But since you are a novice begin with the exact protocol wichever you choose. For me ornithine capsules did nothing to improve sleep. And don't do more that a half cup during the flush.
So, relax and know you are doing probably the most powerful thing for your health! And let us know how it's going :)