I have 2 questions:
What happens if no party achieved a majority? Will we then see a coalition in the UK and who can form a coalition with whom?
The leader of the largest party will become Prime Minister. He is likely to attempt to run a minority government, preferring longterm instability to shortterm constitutional improvising that could backfire. A coalition *might* become an option, if the conditions are just right (ie Labour-LD or Tory-LD has a solid majority but Labour or the Tories are quite far from a majority of their own) but it's unlikelyish even then.
The first is highly improbable. The latter is impossible.