A lot of women have difficulty isolating the pelvic floor muscles, especially if you already have high pelvic tone.
I think trying the exercises with the dilator might help you isolate the muscles more easily.
If you have a gynecologist or physcial therapist that can help you locate those muscles, and help you properly do a kegel exercise, that is ideal.
Many women will tense their butt muscles or abdominal muscles rather then the pelvic floor muscles. So you want to work on keeping all other accessory muscles relaxed, and only focus in lifting the intravaginal muscles. At first it might feel like you aren’t doing anything at all, but the more you practice, the more you should be able to isolate just the vaginal muscles.