there is lots of good advice in here already. ill just focus on steam engine here because understanding these tools and experimenting with building will answer all your questions better than we can...
wire wizard and the coil wrapping tool
@Pegleg Meg linked to both will help you calculate a coil at a resistance. they do it in similar ways, and mostly tell you the same info. wire wizard is more suited to complex coils, but try to learn how both of them work because they both have strengths and weaknesses. experiment by inputting different builds and seeing how the resistance changes as you change the metal types, coil size/wraps, wire gauge, and coil composition. a good build is a balance of coil mass (the amount of metal per coil) and the power you apply to it to get it to heat up fast enough and to the right temp (for you). that balance will be difference for everyone, so it can take a bit of effort to find yours.
the
ohms law calculator will help you figure out how your build will actually effect your setup. once you have a build, you can put your resistance into the calculator, and the output power (in watts or volts) in to find your amp draw. this is important for mech mods with fixed output and no battery protection (if you go over the battery's amp rating it can reduce their overall life span/performance or otherwise damage them/you), and not as big of a deal for regulated mods with variable output and battery protections in them. if you only use regulated mods, this tool will be less useful to you, but its good to know how to use it regardless of its usefulness. if you plan to try a mech mod (highly recommended imo), or if you already use them, this is a very important thing to understand (before you use a mech mod btw
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its a good idea to learn how to use the tools so that you can build what you want/need and understand how and why...you might find yourself needing to build for an unregulated series box, or an istick30w or something out of your normal range. its also good to try other stuff, its easy to find great vapes in every 'style' (mtl, restricted lung hits, direct lung hit/cloud chasing, low/medium/high power, all manner of different mech mod configurations).
welcome to the forums