The thing about Jewish holidays and cooking is that you *can*, but you're only permitted to cook for *that* day. Day is defined as nightfall to nightfall. This means you can't cook on, say, Thursday afternoon for the seder on Thursday night. If you're strict about that, I mean. I am. Since it's necessary to prepare for the Sabbath in advance, one prepares two cooked foods - usually bread or matzah and an egg - before the holiday begins and makes a special blessing. One then puts those foods aside and eats them on Shabbat. This means you have already begun your Shabbat prep and can continue. This also enables you to light your Shabbat candles and things like that.
It doesn't work for days when you can cook and use fire, which is why you can't start Thursday night dinner on Thursday afternoon if Thursday afternoon is a holiday. If you're strict, I mean.
So, how do you manage? There are several ways. First - cook as much as possible in advance. In fact, cook everything possible in advance to limit what you need to do on the second night. Second, if you happen to make a really large dish for lunch on Thursday because it tastes better made in quantity, you can certainly eat the leftovers Thursday night. Third, pick dishes that can be cooked quickly. For example, I'm going to roast potatoes on the second night. I'll cut them up small and put them in a hot oven, and they should cook during the first part of the seder, which takes at least an hour anyway. I'll also steam carrots. My mother-in-law has been known to cook a salmon at that point.
To that end - I'm serving pot roast Thursday night. The pot roast is already done and sitting in my fridge, with the juices in a separate container. It will sit there until Thursday night, which is just fine for that. By the time we eat, the roast will be room temp and the gravy will be hot, and that will be sufficient. I'm serving a turkey for dinner on Wednesday (there's a custom among Ashkenazim to avoid roasted foods and all lamb on the first night of Passover, but no one looks at a turkey and thinks "sacrifice", so I'm making a turkey.) That should work out fine because tomorrow is a weekday, except we can't eat chometz after 10AM and we can't eat matzah until that night. I'm also making matzah balls and a farfel stuffing, plus the stuff for the seder plate and the hardboiled eggs we all eat before the meal.
I haven't vacuumed or washed the floor. I'm exhausted.