Can someone who knows about UK employment law please answer this?!?

Thanks! What's the procedure when being made redundant in the UK? We were given letters six weeks ago with the title of "30 day notice of possible redundancy" so does this mean that they've given us our redundancy notice? We were told at the start of last week that we'd all be finishing at the end of the month, but then two days ago they made three members of staff redundant all of a sudden. Do they get paid up to the end of the month, or only up to the day they leave? Does that affect their redundancy? Can they protest against this as unfair dismissal as why should they go and not others? Also, someone mentioned that there's other pay that we are given outwith our wages for this month and redundancy pay? Is claiming redundancy and what we're owed easy to do? Sorry for all these questions, i've never been in this situation before and am totally confused and worried. The company i work for have been known to pull the wool over some people's eyes, and i don't want to get caught out or done out of money they owe me, due to my lack of knowledge in this area. Many thanks.