What you need measuring tape stud finder hammer nail set flat pry bar drill with screwdriver bit level combination square framing square reciprocating saw handsaw stapler.
Framing around inside windows.
There are several parts that make up the inside framing of a window.
Glue the head casing to the head jamb making sure its bottom edge lines up with the reveal line.
The casing is the framing that goes around the top and side edges of the window.
With a miter saw make square crosscuts at those marks.
The style and material used to make the casing.
Hold a length of casing across the top of the window and mark where it meets the inside edge of each side casing.