In order to do anything more than breath, you need a tax number. If you buy a car the tax man wants to know how you can afford it. If you buy a house he definitely wants to know where the money came from.
Getting the tax number is probably the simplist transaction at any government department. Having said this it is probably best to get a Greek speaker to help as few people in the tax office speak english.
When tansfering money from another country, the bank should provide a document for the tax department. You probably need an accountant to fill in the tax return.
