Congratulations.
Try and get rid of any couch grass if its there. Same for docks and thistles and any other weeds that are there in abundance. Cover with plastic or carpet or pull up and compost. Don't compost couch and before you compost the likes of nettles, docks etc make sure they are dead first - leave out in the sun for a day or two before throwing on the heap.
If you are going to be on the site for some time it may be worth you trying to plan out your area - put carpet paths down, place boards down for the edging of beds etc.
Planting wise - winter cabbages, winter onions, late kales, winter salads, you can sow spr onions and leave them in the ground over winter and they should come away in the spring. Over the winter, plant any fruit bushes - currants, gooseberries, rasps, bare root strawbs, brambles.
You could always plant a green manure for over the winter. Things like rye, phacelia, clovers, ryegrass, forage rye, mustards, vetches etc. They will help smother out weeds, help improve soil structure with the roots, if its a legume cover crop it will leave residual nitrogen for next years crop. Some will stand through the winter, some will be killed off by frosts. at the tail end of the winter, chop down the crop and dig down.
Books - The Veg Expert and The Fruit Expert books are my bibles when it comes to plant specifics of plant times, spacing's etc. I think they are great books.