I have used nursery pots a couple of ways. Some small ones I put inside a large container with a clear lid or some other clear covering, plastic bags, etc. Be sure there are holes in both the lid/covering and the bottom for drainage and to allow soil & moisture to enter pots. Others I have sown and placed a cut off 2L or jug on top of the pot to provide light and air/moisture from the top and still have headroom for seedlings. Some seeds I put a plastic bag over the pot knowing that by the time the seeds germinate it will be warm enough for the seedlings to survive without any covering.

Some pots I cut low to conserve potting mix as seedlings don't need a quart/gal full of potting mix. I prefer using shallow flats or 4 in pots. A cut down gal. pot makes a nice small flat.

Re: covered patio
Winter sowing can be done on a covered patio but containers will need more attention as won't get rain/snow so will need to be hand watered. 1/2 day sun will be enough for germination.

Welcome to the fun.

If your containers are deep enough to allow for 4 inches of growing medium and still a bit of head room, you can just cover them with clear plastic. I use left over window winterizing plastic and tape it to the container. Rubber bands don't hold up to the weather and sun.

Martha