One thing I have noticed about shooting sling shots is that it is not an expensive hobby. Sure, you can amass a large collection of frames, but all you need is one that fits your hands, some bands, and ammo. Here is an approximation of costs. A decent safe frame can cost between $30-50. Band sets are around $4 each in sets of 5. There are frames that you have to attach the band to using small bands or tape. Some frames have screwed clips for attaching the band. The catch box I made is a plastic bucket. I had made one out of a cardboard box initially. The clay ammo I found is $14 for 2500 clay balls. Frame, bands, and ammo to get you started would be less than $75 and provide weeks of shooting.
Also the frame should have a lanyard attached for safety and always wear eye protection. Some use a thin glove to protect the hand holding the frame because frame hits are possible.
At this point I prefer a pinch grip where the frame has indentions that allows your thumb and first finger/index to wrap around the frame. I also like a palm swell so that my hand is filled. I find this more stable.
First thing is to find which eye is dominant. This will determine which hand holds the frame. Secondly, you will decide upon an anchor point that you will draw the band back to. I use the corner of my mouth. There are numerous videos available from people who have forgotten more than I will ever know. Based on your anchor point, you tune your bands accordingly. Longer draws require longer band length and shorter draws shorter band length. The band come long, and you cut according to your anchor point. Again, band tuning videos are readily available.
A catch box or a large frame with a blanket or old rug draped over allows you to capture and reuse the ammo. I am a dedicated clay ammo advocate because, I want an ammo that will dissolve if I cannot find it. Also, if you hit the frame, it will not do as much damage as steel.
I am posting this now because we are entering the Winter months. This is a hobby that will get you outside and give you something to learn and work on during the long winter months. Some shooters will have an indoor range.
I've been going outside in the afternoon after putting a handful of ammo in my pocket and target shooting for an hour or so. I take a break after emptying the pocket, collecting shot ammo, and reshooting. it's sort of like meditation with activity because you learn to learn the importance of breathing out and relaxing, similar to archery or firearms.