Bonjour Fiona !
J'adore is equivalent to J'aime beaucoup = I love / I like very much
The nuance is that you wouldn't use it to express love for someone, as in in love with.
J'adore Pierre ! = I love Pierre, in the sense of "I love that guy!" (not in love)
J'aime Pierre. = I'm in love with Pierre.
You can say Je n'aime pas beaucoup [ça] = I don't like [that] very much
I hope that's helpful!
Bonne journée !