how do I reach an orgasm by myself?

my pelvic floor doctor has given me the goal to reach an orgasm, as I have had some issues with feeling arousal. I also have vaginismus, so I can only really focus on external clitoral stimulation, and even when I insert a finger i don’t feel anything. I bought a rose toy and was recommended to use lots of lube which I do. The pleasure I feel is almost like I have to pee? So I’m not sure if that’s normal or even the right feeling. But I feel all warm and get chills/jolts up my body. However it gets to a point that I feel too overstimulated to continue, should I push past that? Or how do I reach an orgasm from there?