Thanks again, Tony. We put the Betta in his new home tonight. He had to spend a week in a 1/2 gallon bowl, but I could tell he was happier there than in the cup. He has been exploring the 10 gallon tank for a while and seems especially curious about the heater, the plant and the filter.
Thanks to you and to reading this forum, I'm hopeful I'm doing this right. I cleaned out the tank and filter with baking soda and vinegar, then got a 50 watt heater, filter inserts, gravel vacuum, frozen blood worms, betta pellets, some very smooth toys and a soft fabric plant. It is my 9yo's fish and he picked out red gravel and a red plant (LOL) a skull, beachball, pagoda and cave.
I used Tetra Aqua Safe and Tetra Safe Start since I have never owned an aquarium before. It seemed like the easiest way to go for a complete novice. I added the dechlor, filtered the water for 24 hours, added the TSS, added the fish and then crossed my fingers. They are still crossed. If we decide to add a shrimp or another fish or two, I'll be sure to wait a few weeks.
Sorry this is so long, I just wanted to say thanks for helping me have a happy fish and a happy kid. Until I found this forum I thought a 1/2 gallon bowl was plenty for a betta. Now I know why the two we had before over the last 10 years or so always died after about 6 months. I'm thinking this one will do much better and be much happier.