Okay, the EU elections use the d'Hondt system. The d'Hondt system is fun!
Basically you have a big-ass constituency, say East of England. This place elects 7 MEPs.
You vote for parties, not candidates. What you then do is take the percentages, say:
UKIP 30
LAB 20
CON 18
LD 10
GRN 8
Each party then scores what it scored, and half that, and a third that, and a quarter that, and so on, so:
UKIP 30 15 10 7.5
LAB 20 10 6.6
CON 18 9 6
LD 10 5 3.3
GRN 8 4
Then you pick the top seven scores
UKIP 30 15 10 7.5
LAB 20 10 6.6
CON 18 9 6
LD 10 5 3.3
GRN 8 4
And so in this case UKIP get 3 MEPs, Labour 2, Tories and Lib Dems 1.
Does that make sense?