jump start points

Please can someone help with this. It may seem dumb but I don't want to wreck the ECU by making a mistake. Ok so my E300 Turbo Diesel Estate car 1998 with c100,000km on the clock decided not to start. Very unusual. Thinking that maybe the fuel was low, put in 10l and just in case (priming)...

Hi Stupidly left my headlights on over night, battery is dead as a Dodo. I've seen videos on YT that show a red cap you push in to expose a positive terminal and that there is a pillar sticking out on body work for the negative. My van does not have these I can't find them anywhere. The van...