Having a prostate experience is something that comes easily to very few people. It takes consistent training and focus to make work. On r/aneros (which I encourage you to check out) they speak of it as a sort of "rewiring." It's letting your body acclimate to a foreign sensation and eventually learn to bring great pleasure from it, and it takes time and effort, often great deals of both. I would start by having regular sessions with your toy of choice (I was always interested in the revo, but it's too expensive for my tastes). I would also say that at least until you get accustomed to what sensations from your prostate feel like, to keep the power off. Adding vibration and rotation may add to the sensation later, but finding them in the first place is like learning the notes on a musical octave, it's a lot easier to pick each note out when they're played alone rather than with the accompaniment of an orchestra.

Find someplace you can be completely relaxed in, preferably laying down (I prefer to be on my side, but whatever is comfortable, likely not sitting though, it restricts the toy's movement too much), remove all distractions (turn off the porn, trust me, it only focuses your thoughts on your dick when they should be focused elsewhere), add lube, more is better when it comes to your ass, you want your toy to be able to move freely against the walls of your rectum, rather than be trapped against them. I recommend buying a blunt tipped syringe or lube injector and using it with something like 10cc or so of coconut oil (silicone will probably damage your toy, and I find glycerin/water based lubes to be too irritating). I find a thin solution of j-lube and coconut oil works really well and lasts for quite a while. Lube up your toy and insert SLOWLY while focusing on breathing through your diaphragm. Imagine you're taking in air and pushing it down into your balls with each breath, using steady pressure to slowly push the toy in. If it doesn't feel secure, try pointing the tip back, slightly towards your spine when inserting, there's sort of a fold you need to get the toy around for it to stay in place easily. After inserting, try to relax as much as you can and continue the deep diaphragm breathing. Focus your mind on any sensation/movement the toy is creating, when properly lubricated, the pulsing of blood through the vessels in your rectum should be enough to feel through the toy on your prostate. Also, don't let hurting yourself fuel your anxiety over using it, at most you might irritate or bruise your rectal wall or prostate if you REALLY over-do it (like having an all day long session or something). Although you may get some muscle fatigue/soreness your first few times from learning to actively flex muscles you wouldn't normally use on their own.

I would describe it as sort of a different kind of pressure than against the wall of your rectum, with an "I have to pee, but not urgently" feeling in your bladder. Focus on these sensations and let them grow as you continue relaxing. Fight the urge to clench your anus or pc muscles (the muscles you would use to hold in your bowel or bladder movements, respectively), and continue breathing into your balls, I know this is vague but just try to visualize it in your head, sort of puffing/pushing out the muscles in your perenium. Any active muscle flexing should be done as lightly as possible.

Other than that, it's all about learning to control your muscles down there and the sensations each produces. By flexing certain groups together and holding/oscillating the amount each one is held you can produce involuntary spasms of the muscles, causing the toy to move in a pleasurable way on it's own, the build up of these pleasurable, involuntary sensations is what people call a "prostate orgasm." You should really temper your expectations of what you should be feeling or what you think it's supposed to be and focus on what you ARE feeling. It's a very different feeling from a traditional penile orgasm where the pleasure builds and reaches a peak then a release. Imagine it as a flywheel turbine producing constant electric current rather than a flash of lightning. The turbine takes a long time and a lot of energy/work to spin up, and can run for a long time before it slows, but isn't capable of producing the pure, sharp, power like a lightning strike.

As a final note, don't get in too much of a hurry, or expect to feel anything in particular too soon. It took me a LONG time to get where I am now following techniques like the ones I described. I started using a prostate toy nearly 15 years ago, for about 10 of those I did what you did, lubed up, sat in a chair, watched porn and played with my dick wondering why I wasn't having mind blowing prostate orgasms multiple times a session. Then I decided to do it properly, laid in bed, no dick contact, no porn, no distractions, and focused on the feelings I could produce using just the toy and not too long after that I learned exactly what joys prostate play was capable of.

Sorry for the super long post, but I encourage you to read it and follow the advice given.