How should I use PAINT SPRAY on raw wood ?

You shouldn't, get some Kilz first and spray on a light coat of primer.

No, you need to prepare the wood properly before using spray paint.

Put down a primer first. Many top coat paints do not stick well to bare wood. Read up on the paint you are using and check around before you buy any paint. One thing that kind of should be a worry is your being at a level of asking a question about paint and you are using a spray gun. Unless you are out of a can. In that case, buy a case fulll and blast away. To answer your question. Tape off and cover what you don't want painted. Then buy the correct paint and apply with a good brush. Most work in painting is preparation, not the actual painting.

you need a Hi Volume Low Pressure sprayer system for stuff like that

use self priming paint