README: document how to build

README.md

@@ -2,11 +2,22 @@ OpenSCAD model for Case for PinePhone
 
 based on [beattie's earlier model](https://github.com/beattie/PinePhone-Case).
 
-WIP phone case for the PinePhone, and associated models.
-
 files:
-- dimensions.scad: dimensions used to build phone module
-- bits.scad:       modules for the bumps on the phone to make holes in the case
-- fillet.scad:     form a rounded bump around the screen opening
-- phone.scad:      a module to make a model of the phone use to carve out a hole for the case
-- case.scad:       make a model for the case
+- case.scad: top-level/entrypoint.
+- defaults.scad: tunable settings which affect the detail of the model.
+- dimensions.scad: measurements of the actual PinePhone, used to assemble the bits.
+- phone.scad: model of the actual PinePhone itself; the case is made by constructing a shell from this model.
+- bits.scad: models of all the cutouts/extrusions which exist on the phone. i.e. buttons, ports, camera.
+
+## use
+- compile the scad to stl:
+```
+make build/case.stl
+```
+
+- slice the stl file using slic3r:
+```
+make build/case.gcode
+```
+
+- then send `build/case.gcode` to your printer.