Criminal law deals with matters where people have acted contrary to "Statutes" (which are laws made by Parliament) and "Common Law" (which is law that has built up historically and has been accepted, though no Statute exists). Murder, for example, is contrary to Common Law).
Civil law deals essentially with disputes involving contracts and "tort". Tort is where no contract exists but damages may be claimed. For example, if you trip over a loose paving slab and sue the local council, that would be as a result of a breach in tort. You have no contract with the council but they have a responsibility to keep the pavements in good repair and if they don't they may be liable to pay damages.