(...)
The following months:
Even after officially announcing to leave the EU, things will remain at current status quo for the next two years, which means all British EU officials will remain in their jobs for the time being. Same goes for the British members of the EU parliament. The British government will be busy preventing another attempt of Scotland becoming independent.
The EU will try to make the Brexit as painful as possible for Britain in order to prevent other countries following the British example. A further participation in the common EU market will be very expensive for Britain. In the end the cost might be higher than before because no money is coming back from Brussels anymore.
Cutting all legal and contractual ties with the EU will probaby take two years. Then the relations between Britain and the EU need to be newly negotiated. All 27 member countries and the European parliament will have to agree to the new terms. The whole process is expected to take at least five years.