Dont panic, I was exactly the same as you, needed it and it scared me.
I found the 3ft poles better than the 4ft poles.
I used tape rather than rope{heard that rope dosnt give if something gets tangled up in it}
You can get an energiser that runs on d cell batteries but i used it and its not very good, PLUS you must make sure you take them if u want to connect to a car battery.
I bought my car battery from breakers yard{they have hundreds and all tested}
The energised is pushed into the ground which acts as the earth stake too, then has a wire which attaches to the tape, if you make sure you use 1 constant line of tape then all of them will be live{I made this mistake and peach found the one that wasnt live and went through it!}
DONT forget to get something to act as a gate or you end up untying it all the time, i used a couple of the spring gate handles.
Hope that helps
ps i heard they do the posts in prety colours now too!