Get used to building the RDA and using it on a regulated mod before putting it on your mech.
Look at lots of tutorials on winding coils and installing them properly and safely.
Look at tutorials on how to wick your coil, how much cotton to use, how to trim it, how to prime it.
Make sure you have the right tools.
Look at Battery Mooch's videos on YouTube about battery safety and mech usage.
Look at tutorials about mech safety and how to strip and clean and safely reassemble your mech. Understand exactly how your mech works.
Understand the vital importance of battery orientation in a mech.
Understand that a mech won't give you a better vape than a regulated mod - it's all about form factor and the simplicity of mechanics. It's like the difference between a classic 1960's sports car and a modern hi-tech supercar. The classic car has less parts to go wrong, is easier to repair, but doesn't have any driver aids to help save you from crashing. The classic car wont perform as well as the modern hi-tech supercar, but to some that's not what it is all about.
Be patient, don't rush, enjoy the learning experience.