And the Wait Begins...
It usually takes a few weeks before the offers start coming through. You may be given an offer conditional on obtaining certain grades in your upcoming exams. The offer may either take the form of specific grades you are required to get in upcoming exams or as a points offer which can be made up in any combination of grades. For example, 'BCCc' would require you to get a B grade in one of your exams and at least C grades in two of the others as well as a C grade at AS level. If you did not manage to get the exact grades they could refuse to take you on the course. A similar points offer may specify 300 points. If you do better than expected in one of your exams, you can compensate for doing badly in others.
More details about the UCAS Tarriff points system can be found at the UCAS website.