There's bound to be a million write ups with pictures using a google search. Just don't be dumb about it and you'll be ok. If something seems unsafe to you, then it probably is unsafe you know what I mean? Don't bungee cord the battery down, don't use tape as a sole means of routing wire, don't use too small gauge of wire or connectors, ... If it looks wrong, it is wrong. Bolt or weld a tray down in the trunk, use correct tie downs, use heavy gauge wire and connectors, route your wires in a manner they won't be cut or messed with... Simple