@bwh79 gave you some good advice, but I'll add the following:
As a new builder, you really should be focusing on becoming extremely comfortable with the basics before looking to build potentially complicated, cloud chasing builds.
It is imperative, IMO, that you are adept at building simple coils with round or twisted kanthal (or nichrome) before proceeding further. The good news is that there are plenty of very simple and straightforward builds that will still produce excellent vapor.
Here are a few of my favorite builds made with round or twisted kanthal for the Velocity. Some of them are more in-between a flavor chasing/cloud chasing build, but they all put out good vapor. They are all dual coils as the velocity is essentially dual-only without getting fancy, and duals will give you better vapor anyway.
1. 24g kanthal, 7 wraps on 3mm ID, should come out to ~.7ohms per coil and .35ohm for the duals.
2. 2-strand 28g twisted kanthal, 8 or 9 wraps on 2mm ID, should come out to a bit more than .75ohms per coil and .37 or so for the whole thing.
3. For better battery life and still decent clouds, 28g (not twisted), 8 wraps, 3mm ID for .8ohm total.
4. This is lower than you really need on a regulated mod but one of my favorite builds, period: 2-strand twisted 26g kanthal, 2.4 or 2.5mm ID, 5-6 wraps and should come out somewhere between .22-.28 for duals depending on the wrap count.
There are four different coils right there, and there are literally an almost infinite amount more you can build before reaching past round and twisted builds. Parallel coils are also popular for cloud chasing, but more difficult for a beginner than simple round kanthal or even twisted IMO. There's no reason to move too fast with building unless you have a particular love and knack for it. Especially depending on what you were using beforehand (be it another device or cigarettes), switching to an RDA is typically a big change. When I got my first RDA I was amazed at the clouds I was getting out of it with a simple .5ohm single coil, compared to my older stuff.
Go slowly and be safe. If you find you absolutely can't get enough of coil building, then you can start looking into some true cloud-chasing builds. For now, there are simple builds that are within most new builders' skill sets that, with a 100W regulated device, will produce even more vapor than you are probably expecting.