O/T..but i need help PHOTOSHOP ???

i am doing some letterheads for my dad and he needs the DPI at 600. i have never had to change this and cant figure it out..sorry for takin up board space with this but i cant find an answer anywhere

 

If you start from scratch, select
File
New
And there you set width, height, and Resolution
´Resolution is the one that should be at 600 Pixel/inch

If you have a picture
Select Image
Image size
The select 600 Pixel/inch in the Resolution box.

Hope this help's

 

ahhh..thanks