Buy your favorite wood see craft store or hardware store.
I went with poplar it was light and easy to work with.
Sand with hand or use sander go with grain of wood.
Not much grain to see but really smooth.
Set up a mock up of what you want to build. I found the silver grommets to give a finished look.
Lay out your cuts with pencil on wood.
Mark iPhone size think small easier to enlarge later.
Drill speaker holes
Clean up with roto zip /dremel or router .
First pass with roto zip go slow and take a little bit off at time.
Note small increase.
Test fit again.
Drill holes for speakers into speaker cavity (see small black holes next to charger)and drill hole for charger.
Bottom of charger cord.
Test fit then hot glue in place.
Check it out, I was surprised at sound increase from speaker cavity connections.
My 14 year old daughter loves the retro look and how it sounds. She is pretty proud of her dad.