Ok so for clouds you have 2 main factors.. coil surface area and power. The bigger the coil surface area, the bigger your cloud and the more power you need to fire the coil.
So that said, pick your mod based on the most power you can afford. Get a DRIP atomizer, I think MutationX are among the best for cloud builds, some wire, cotton, an ohm meter and do a lot of google searching on cloud builds. Taller atomizers with wider bore drip tips make bigger clouds. More air flow means you can run higher wattage builds and keep the temperature down low enough to vape it. (air flow cools your coils and vape).
Main thing is .. you build to the mod you have and maximize your cloud by building your coil tuned to the mod you purchased. Example.. a dual coil, 6 wrap build using 20ga stainless steel will run fine on 200w but a dual coil, 10 wrap parallel build using 20ga stainless steel will give more cloud, but you need around 250w+ to fire it.
As a beginner, 75 to 100w is a good place to start. It takes time to get used to vaping on a cloud build. LOL.. I've seen competitors choke on their cloud in a competition.
I have a few vids on my youtube channel with different atomizers if you want to compare a few. Username is gbalkam. MutationX V4 and Temple will be the main cloud atomizers I use.