darrenfos, accept what you have bought is a heap of shite, and won't ever work right.
BUT if you must fit the useless bloody things, based on the half answers you have given to the queries we've asked in order to help you, here are some thoughts:
When I looked it up on the internet, that device needs a speed signal from somewhere, so there must be more that "just 2 wires" (beyond the 4 ultrasonic sensors). Just connecting up the 2 wires will not work properly, unless you like driving along listening to beep beep beep all the time - that would get on my tits, and I'm sure yours.
These, you say, are Front sensors. You are reading instructions for Rear sensors (hence the instruction to wire up to reverse lights). If that is the only instructions, ask the supplier for the proper instructions - may as well ask for the correct current draw at the same time.
It absolutely, categorically, completely, 100% MUST BE FUSED. You never answered the queries about the wiring cross section, so we cannot tell you fuse size. Given what you have said, I would not go above 1A, though I'd be more cautious, and go with 500mA Quick Blow fuse.
I wouldn't wire into ciggy lighter - that takes enough abuse dealing with other shite plugged in, I'd look for another suitable switched 12v feed with enough capacity to spare 1A (which rules out seat feeds). The ign feed to radio may be sufficient, depending on radio fitted.
If there is no speed signal to wire in, and no dash switch, send it back with a note along the lines of "This is a heap of chinese junk, please refund in full". Certainly the blurb on the net implies it uses a speed signal. Either it must detect speed, so it only works at less than 2mph etc, or there must be a switch to enable and disable it for when you want to park. If not, the thing will be constantly beeping when cruising down the motorway.
If you provide answers to questions asked, you are likely to get some help. As it stands, from what little snippets you have given us, we cannot tell you how/where to fit. Although by the sounds of it, it doesn't sound like its worth fitting.