Special - Seder on Motzei Shabbat
1. Chametz and other preparations
Pesach needs to be ready exactly as if it were Friday night Seder - searching for chametz Thursday night, finishing chametz and burning chametz Friday morning, etc., get as much of the Seder ready as you can, because you can't make any preparations during Shabbat - and Pesach starts late, after nightfall.
With daylight saving time, this means that the less you have to do motzei Shabbat - the better - especially as you must also finish the afikoman before halachic midnight. At least you definitely get a rest on Shabbat afternoon - and then you can have a light meal after your siesta.
You'll need a 3 day candle from erev Shabbat, in order to light candles motzei shabbat and Sunday night in the Diaspora. Candles for Pesach are lit at the time for the end of Shabbat, and preparations for Seder may not be made before this time.
3. Making Hamotzi on Shabbat with bread
You can use bread for hamotzi in some other place, carefully, for both meals; the morning meal will need to be after very early minyan, with bread eaten before 9-ish or so (times available on calendars and in Jewish newspapers), this can be eaten as seudah shniah (brunch) and seudah shlishit can be at lunchtime, without a need for bread. Use disposable cups, plates for each bread piece eaten, wrap them up - none to wash.
A. You can use a disposable paper tablecloth and utensils and make kiddush, hamotzi over it very carefully, then clean it all up (clothes included), sweep up, and clean remains off anything you use straight into the toilet, leave the utensils in the disposable cloth and wrap it up tight. [Paper, not plastic, because you need to burn it all on Chol Hamoed!]
Then change the cloth and put on Pesach stuff.
B. Or you can make hamotzi and eat the bread on the front porch/outside/on the balcony, because it's definitely easier to clean up and won't mean checking your living area.
Then take a drink from the bathroom tap, rinse out your mouth and brush your teeth, then put away the chametz toothbrushes.
Wrap up any crumbs to burn first day chol hamoed, as for any chametz found on Pesach.
4. Making Hamotzi on Shabbat with matzah ashira
The Sephardi and Israeli custom is to use matzah ashira, rich matza, so that there is no chametz in the house after burning it on Friday, and it can be eaten at the table. This is increasingly the accepted and recommended solution, but it's not always available in Diaspora communities.
However, Ashkenazim only eat egg matza before the last permitted time for eating chametz, so it still means having lunch at breakfast time and being careful, but it's not as bad.
5. Best online references:
** the most thorough and relevant!
5. When to make Havdalah
Havdalah is made during Kiddush that opens the Seder, it is in the Haggadah as the preface to Kiddush; it has to be after nightfall, obviously.