The Demi part means that you're not romantically attracted to
people unless you form a strong bond with them. Therefore, when you see random
people or whatever, you don't feel attracted to them unless you fall for their personality after you get to know them. So, you don't really get "crushes" like most
people do.
The Panromantic part means that if/when you fall for someone, they could be any gender, meaning that you could be attracted to any gender or gender identity.
The Gray-
Asexual part means several things, but for example: you feel sexual attraction infrequently, or a low intensity of it, to few
people, or only in specific circumstances; that you feel sexual attraction but have no desire to act on it; that you have ambiguous or confusing feelings toward sexual attraction; or that you feel that sexual attraction is not a meaningful concept to you.