I am not a professional though but my advice is :
Things you need :
Aluminium Foil / Plastic Bags
A Engine Degreaser like 3M Engine Degreaser Foaming Spray
A engine detailer like CD2 Turtle Engine Dressing
A couple of Brushes
Some warm water
A wind blower or a spot below a fan
4 hours If not having a blower
Procedure : Warm up engine for five minutes It should be warm not hot
Cover distributor, Air intake, Fuses , And Electricals with plastic bags.
Spray sufficient amount of degreaser on whole engine.
Now brush away chunks of dust and grease. Wait for 15 minutes. Now the important part use low pressure warm water I preffer first spray water with spray bottel then with a hose. After applying water let it dry. If you have blower use it if not then park car under a fan for a hour atleast. Now remove those plastics covers make sure all plastics are removed. Use a dry cloth or damp it little bit to clean plug area distributor and covered parts. Now apply a good coating of detailer and clean excess with a clean cloth. Your rides engine is now detailed.
P.S Do remove battery terminals first If you don't you will be in problem.
Please ask a expert first because I am a newbie
Happy Detailing