Clueless but I want to make a module.

[Cursed]

Where should I start? The wiki's how-to pages are mostly borked. What I want to make might also be overly ambitious too, I want to make the skill system classless kind of like the Dragonball-T module, but with the trainers only selling skills in large packages that change as you use them instead of being able to choose from an assortment. Aside from that I want the game to revolve around a giant arena with the player only leaving the main city to find trainers and loot to use to get further in the arena. So that probably will require a lot of stuff for special arena levels to be warped into and spawning monsters, having an arena ranking (possibly in multiple categories), etc.

I was thinking I should try to just implement a basic arena itself first, then add in some extra random dungeons to loot, and add more depth to the character growth and arena later on, as well as special levels and side quests to meet trainers and find artifacts. But I don't have a clue how to begin at all when things as basic as making your own town have no documentation.

[Xandor Tik'Roth]

I have no idea how to code, but I would recommend that you first start off simple to get a feel for how to work the system. Take the ToME module apart and put it back together. Maybe add in some monsters. Create a new dungeon. A new special level. That sort of thing. If you can do that easily, building a new module should be a breeze.

[Shoob]

actually, I would disagree with taking the ToME module apart...

you want it to look a bit like DBT, I would be hesitant about tweaking that as that is a LARGE file... is there something that you want your module similar to in another module, such as zothiqband or ODE, or BOB? then I would use them as a base and go from there

so if you are looking for just an arena... I am not sure what I would choose probably zothiqband as there are shops and stuff in that... then I would look at the npc code in DBT to get used to the syntax for the trainers.

so reading the code for existing modules similar to your idea is best, but I would stay away from larger or broken or previous versions of modules.

[LordBucket]

Where should I start?

Pick a module and start changing things. First thing you need to do as a new module maker is learn the engine. Last I checked, Zombie Horror was generally the most friendly to new module makers. I'd recommend you download that and start making changes. Like Shoob says...Dragonball T is monstrously large. It may be more than you'll want to tackle to begin with.

I want to make the skill system classless kind of like the Dragonball-T module

DBT's skill system should be easy to port. The relevant script is scripts/enroll.lua. I don't recommend you start adapting it as the first thing you do, but I think it's safe to say that once you're generally comfortable around the engine, adapting DBT's enrollment system won't be terribly difficult.

I was thinking I should try to just implement a basic arena itself first, then add in some extra random dungeons to loot, and add more depth to the character growth and arena later on

Yes, that would probably an excellent way to start out. Why not give it a go, and ask here once you start running into more specific things you'd like to know about? T-engine doesn't have a lot of documentation, so jumping in really is the best way to learn.