It will be a little challenging to put everything together from what has been already said. All true facts. Research, research, and do more reserch until you decide what mod and RBA will best suit your vaping needs.
A regulated variable voltage mod like an MVP would probably be the most logical next step. It will be more customizable due to the variable voltage to adjust to your tastes and moods. It will most importantly have built-in protection circuitry to keep you out of harm's way should you make a mistake. Will include a built-in voltage and ohm meter, which comes in handy. Due to that protection circuitry and amp limits of the processor, it will not be able to do sub-ohm.
A mechanical mod is just a battery holder. No protection circuitry, no ohm or battery meter. The only way to adjust your vaping experience will be to change the entire coil out. The only advantage a mech has over a regulated mod is that they can fire a sub-ohm coil by bypassing protection circuitry. But having no protection circuitry means you have to know what you are doing, because a mistake or unexpected error can result in a vented battery or worse.
Rebuildable drip atomizers will be the easiest RBA to learn on. The build deck is right there. You can get the largest "clouds" with these. However, they only hold a little bit of juice, and you will need to bring a bottle of juice with you everywhere you go.
A Kayfun-style tank will be more convenient for out and about use. Juice capacity of 4 ml. Great flavor, just better than average vapor. Downside is you have to drain the tank to reach the coil and wick, but not reallly a huge deal. For some there is a learning curve.
I do not recommend a Genesis-style RBA as your first RBA. More complex as you are fighting gravity, more difficult wick preparation, they leak if not kept upright, and you have to tilt the tank to get it to wick properly. Highest learning curve.
Inexpensive Mech Mod/RDA Setup
Ohms Law for Dummies
Battery Basics for Mods
Deeper Understanding of Mod Batteries
Information Resources for Your First RBA