You may also find this to be helpful, especially Steps 6-12 and Figs 6, 7, 8, 9, 10 & 13.
http://www.installuniversity.com/mb/w203/w203/trans_oring.html
FWIW, I had about 1/2 liter of ATF pour out of the connector hole when I pulled the electrical connector. Elevating the front end would minimize this while also providing easier access.
Lube that new adapter well with ATF prior to installing. It's a VERY tight fit.