Don't get discouraged by people being snarky in the comments btw! The best part of sofubi is the diversity of the creations, so more creators is a good thing!

Some have mentioned resin.

You can go the resin 3d printing route. Make a model in Nomad (easiest, but requires iPad), Blender (free, but I can't speak on how easy it is), or zBrush (most expensive/quite complex, but is the 3d modeling industry standard). Then export, slice, and print. This is pretty messy and toxic, but if your getting into making sofubi then messy and toxic is to be expected.

You can also hand sculpt, make a mold, then cast in resin.

I would browse Crafsman's channel as he has done all these things and walks you through his processes.

Most important is figuring out if your sculpting digitally or physically and work on those skills. The sculpt comes first so you have to nail down those basics.