I would start seeds off indoors on a sunny windowsill rather than straight in the ground to give them the best chance of germinating. Ideally in compost, so if you can get hold of any I would hold some back when forming into the soil.
If you can't find compost, I would dig an fork over the soil anyway to get it as broken up as possible before planting.
In terms of what to plant I would go for relatively easy veg, that gives you a decent yield to effort ratio, and of course only ones you enjoy eating!
I've grown things before but still quite a beginner. This is what I am planting to keep things simple for myself:
Runner beans - supposedly quite easy and can be very productive, so I am hoping the reward to effort ratio will be good. Also I have some seeds already which I never got around to planting last year!
Peas- kelvedon wonder, I have grown these before and fairly easy. They germinate very easily too. My DC like to eat them straight front the pod so a good way to make them eat veg!
Just approaching optimum time to plant and grow peas and runner beans, so still time to order and germinate.
Potatoes - I have not grown before, but seem straightforward. Seed potatoes still available online - I ordered from my local garden centre's website. I am going for Jazzy "second earlies" and King Edward "maincrop". I am also experimenting by attempting to plant some sprouty supermarket Maris pipers. I am chitting them first. If planting in the ground apparantly it's good to prepare and warm the soil first, by leaving black sheeting (could use bin bags?) Over it while the potatoes chit. A little bit later than ideal to start planting potatoes, but ok I think.
Tomatoes - don't plant in the same bed as potatoes! They like very rich soil I think. Can you get hold of veg fertiliser if no compost?
I am also trying to germinate parsnips and leeks from out of date seeds (found when rummaging through seed tin). And "patty pan" squash from some in date but old seeds.
I am not going to bother with hard crops like carrots.
Fruit - in the past I have had great success with strawberries, including alpine strawberries from seed. They grew really fast, and sent out loads of runners so I got extra plants.
Herbs like rosemary, thyme, mint, chives grow well outside. Some salad too.
Most of my growing is in pots. I ordered coir compost as this takes up less space in transit, and I am enriching it with fertiliser. Not ideal but needs must!
There is loads of info and tips online about what different plants need and the best way to grow them (earthing up potatoes etc) so well worth spending some time researching whatever you do decide to plant. Of course in real life it is often not possible to provide ideal conditions, still worth trying anyway!