It is not difficult, but the 'little details' that the instruction mention ARE important, so don't try to do it 'quick & dirty'.
1) first, use some other tape (electrical, friction, etc.) to hold the cables in the desired position on the bars.
2) use small sections of tape around the brake levers - it is difficult to get complete coverage with the main tape.
3) start at the bar ends - that is so the wraps overlap so that your hand pressure is not pushing against a 'high side' of the tape which would cause it to fray or unravel.
4) wrap the left side counter-clock-wise when viewed from the rear, and the right side cw - this is so that when you lean on the tape near the stem it causes the tape to tighten.
5) wrap the tape with even tension and amount of overlap - that will give the best 'feel' and looks good.
6) finish-off the wrap near the stem with the special pieces in the tape kit, or with electrical tape.
Jay Kosta
Endwell NY USA