In terms of what type of toy you should start with it, it really depends on what you are looking to achieve. Butt plugs are designed to stay in place, so if you want something you can just pop in and get stimulation without doing much, then they are a good choice. If you want a thrusting sensation then you would be better off with a dildo. Anal beads are designed to be pulled in and out, and particularly removed at the point of orgasm so are a more active toy, but to a lesser extent than a dildo.
I’d suggest having a think about the size of the things you’ve played with (be that fingers, tongue or a penis) and if you could take then ok, go with something around that size. Your eyes (and brain) are more important here than your actual butt. If you look at something and are intimidated by the size, then you are less likely to be able to take it (even if you’ve had large in there before). Generally with butt plugs, ones labelled medium are fine for beginners.
I’d second @rockstar’s suggestion of a t-bar base, I find them much more comfortable. If you fancy trying glass and you’re not a complete beginner to anal play then I’d highly recommend this one:
I’d say it’s a little on the large side for a complete newbie but if you take it slowly it’s lovely. I didn’t start with a beginners plug, I think mine had a 5 inch circumference but it was a soft silicone so easily managable. I enjoy plugs and dildos, it really depends on my mood. I’d recommend trying both to see what you like.
Silicone butt plugs are gentle to insert (with lots of water based lube of course.) Take your time and be patient inserting. Your body will relax and release over time with constant gentle pressure. Never force, if pain stop immediately and add more lube. Flared bases are safest as you never want to lose a toy inside yourself. For cleaning afterwards, shampoo or good toy cleaners work best and keep your toys fresh. Have fun and explore.
When I first started with anal toys, I started with this
I prefer to be clean when doing anything anal so the included douche was a nice addition to a beginner kit.
If you’re just introducing yourself and don’t know if you like plugs, buying one smaller silicone one would be a nice start.
Or if you’re confident you’ll go up a size, 3 piece sets could be good
I’m rocking these , 3 sizes which would be perfect for seeing how you like it before trying anything too big.
Toys are a great way to start. You can take it slow, never rush. I would recommend a set like below, the base is T shape which I have found comfortable. The thin neck give you confidence of placement and when you relax it is more fun. A good cleaner is also highly recommended like below the set.
I am also in the vibrating tee plug camp . For me it is about the only one that will stay in while moving about . I have one I have had for years and I still use it often for warm ups before moving into toys of more stature . I remember “several” years ago when we bought a stater harness with two plugs . OMG ! Even the smaller was good sized and and I thought she was going to have to run at me to get that one in . Here is a suggestion .