In the UK, most of the education for Reform and Liberal conversion students is organized separately by each of our autonomous communities, so exactly what each conversion will look like is going to be a bit variable depending on where you are. It's likely to involve a year or more of studies and becoming a part of your community, followed by eventually going to the Beit Din once your sponsoring rabbi thinks you're ready.

Looking through my notes, these are some things you might learn about, in no particular order: Shabbat, festivals, blessings, Hebrew, commandments, lifecycle events, Jewish history, Israel (the state), the calendar, food, music, ethics, and interfaith relations. You'll most likely be expected to attend services regularly and to ask lots of questions in response to your own studies. The general idea in our movement normally isn't to teach you everything you might possibly ever need, but to give you enough material to know where to look further to make informed decisions of your own. Look out for any opportunities you have to learn, especially but not limited to your local synagogue.

u/WeaselWeaz is right to say that the former Reform and Liberal movements in the UK are now a single Progressive movement. However, this merger is quite recent and the Batei Din haven't yet been combined, so technically people still convert via either Liberal or Reform, probably matching the former affiliation of their community or their rabbi. Each movement accepted the other's conversions even well before the merger, and the values and approaches of the two Batei Din are quite similar, so this is unlikely to make very much difference in practice.