Help with AHK electrics

Hello, I would like to build an AHK on my Yaris, or am currently with the electrics. The following instructions: http://www.ahkupplung.de/ebay/Bilder/993007.pdf Unfortunately I have no idea about electrics so far. Now there is a long red cable there, that will pull (with safety in between) yes permanent plus. Where can I pick this up best? Do I have to go to the engine room until before? How do I recognize permanent plus if I should find cable somewhere? It is also incomprehensible to me the page 4. There wi rd now some lamp (why the armature appears in front?) left and right ONLY left connected. This is apparently connected with the enclosed current thieves. But why should I strip the cables “gy” and “gy/wh” ALSO again? The plugs are already mounted by the manufacturer?! (see page 2 at the delivery). Hope someone can help me. Thanks. Edit: The whole thing is already summarized on page 3 with the scope of delivery. Why do I have to use already connected plugs again. Remove each other and strip off?!