Hi flo240108, welcome to the site
Being cautious about selling online is actually a really good start right there. Nothing at all wrong with being careful, if more people were cautious when they first start we would have a lot less scammers making easy money of them!
There isn't anything about online trading that you can't learn here, we cover the lot, and a good place to start is to read the information in our education centre, then browse through the forum.
Anyone who has been involved in this game for any amount of time will tell you research is king, the more you learn, the more successful you can be.
Once you get yourself educated on the basics of online trading, then it's a good idea to tell us about the type of products you are interested in selling, the avenues you want to sell through and supply resource best suited to your situation.
The helpful customer support staff will then be in a good position to narrow down some possible supply avenues for you to look at, as well as provide advice on any area where you're not yet fully informed.
Great community spirit on our forum, we're all here to help. I'm not just talking about the support staff, but we have plenty of contributing members that are always happy to share their experience and hand out some good advice when you most need it : )