It is pretty simple.

I have grown chillies and peppers in pots/bags for years.

If you want them to grow well, largish containers are the way to go. I use 25L grow bags (~7 US Gal) to grow them.

You can use the seeds from fruit or buy them if you are looking for speciality varieties.

Plant in seedling pots, seeds usually take between 1 and 3 weeks to sprout.

Replant when they have grown about 3 or 4 sets of leaves.