It's pretty easy and you'll loving it!
-curtain hanging wire hardware from Ikea $12.99
-screen fabric $39 from amazon
(you could also use a white sheet or tarp)
the advantage of screen fabric is the correct gray color for projector contrast and black out backing
-1x4s for frame $20-30
staple gun, staples, screws, drill
1. Hang curtain hanging wire between trees or posts. mount curtain hanging wire hardware in trees.
use 3" long exterior screws.
2. Build Frame
Buy a screen through amazon has instructions to build your frame depending on the viewing ratio you want.
There's also more steps to create a professional, black border which I haven't done yet in this post.
Build frame with 1x4 in 8 foot lengths.
3. Staple Screen to Frame
Center the fabric and staple a few at the top/bottom centers, then the sides.Start at the centers then work to the corners.Pull and staple your way to corners, making sure to stretch out any wrinkles for a smooth, tight surface.
4. Hang with hooks and eye screws
Using 3 hook screws $1.20 each along the top of the frame, the screen hangs on the wire.
To prevent it from swinging forward and back, use small bungee cords to connect the bottom of the screen to the tree trunks
with eye screws from the frame.
The back of the screen is just the open frame.
you'll still need to make a cover for the screen if storing it in the garage or storage and don't want the surface to get dirty or ruined.