Q.Zucchini soil ?
Whshould I use a store bought soil to plant my zucchini seeds in, or can I get better results if I make a compost bin, and plant the seeds in that?

Composting is great, and a super way to create organic garden material. Composting will take some time, and in the mean time you can certainly purchase garden soil to plant in.
Here are some links with more information.
https://www.gardeningknowhow.com/edible/vegetables/zucchini/growing-zucchini.htm
https://www.gardeningknowhow.com/edible/vegetables/vgen/vegetable-garden-soil.htm
https://www.gardeningknowhow.com/composting/basics/starting-compost-pile.htm