Welcome to Leatherworker.net!
You've got a good starter set of tools for basic decorations, and a set of chisels and rotary punch for punching lacing holes....some modeling tools, and some odds and ends. Looking at the modeling tools, it appears they are the most used, so I guess one of your forebears did a lot of hand decoration. Don't worry about it, you've either got it or you don't, and there have been things posted on here made with a manicure set that were just absolutely beautiful. Since you're more interested in building instead of decorating, I suggest keeping them for sentimental sake....and you might need one, one day.
In any case, we're glad you found us. So, pull up a chair and stay a while. Coffee should be fresh, bathrooms are down the hall on the left, and don't eat the donuts.
If you're interested in sewing some pieces together, you'll need to get a few other tools- mainly a decent awl for punching stitch holes, some needles, and some thread. I got my awl from Tandy (Springfield Leather has the same type), my needles from Walmart (upholstery type), and my thread from Hobby Lobby (On-a-string brand waxed linen). There's a TON of info here for free, or you can invest in some leathercraft books from several of our suppliers (see ad banners at top of page). Ask questions as often as you like, but be ready for a lot of reading in the answers.