ooooh ... I just bought some of that stuff.
I expect it to be a ailry firm plastic tape but with some stretch - obvioulsy it cannot be too eleastic as it would be pushed into the hole by the air pressure in the inner tube.
The last bit is always a pain but putting a scredriver under the tape and then moving the tape over sorts it - likewise if you need to cetrnalise the tape, use a screwdriver under the tape and over the rim and go round the rim like that, repositioning the tape (harder to explain than do )