Firm fabric such as upholstery fabric
1 cheap narrow belt I got mine from a highstreet store beginning with P
lining material( I used a soft fleece so as not to damage the device
Methid
Measure your device
Add one inch all the way round
you need two piece of material for the back and front
The pocket
You need another piece of material for the pocket
Cut a piece of the top of the pocket material
cut off the buckle and bottom of the belt
insert the buckle into the two piece of pocket material in the centre and stitch
Make a small tab and insert the other end of the belt into it.
Use the remaining belt to cut in half for the handles.
Assemble all together
the pocket, the two sdes and stitch leaving the top open
Stitch the lining
Assemble the outer bag and the lining inserting the tab to coincide with the buckle in the centre so that overlaps and can be fastened and the handles positioned in an appropriate place.
You can make a small er version for your E reader or i pad