Hi well done on getting a plot. I got my plot 5 years ago this week, it was a bit of a scramble but I did get crops from it the first year. I went up the first day and tidied up any rubbish (just piled it up at the front of the plot) and on my way home I stopped at the garden centre and stocked up on any seeds that said June/July sowing, compost and a pack of cheap module trays. I got up early the next morning and sowed everything. I had lettuce, scallions, spinach, cabbage, purple sprouting broc, kohlrabi, kale, pak Choi, corgettes, French beans and some parsley. I also bought a couple of trays of plants that they had in the garden centre and potted these on into pots because they were getting a bit root bound. That night I strimmed the plot back did a quick measure of it and went home and sat down with a pencil and paper and did a quick plan of roughly the layout I was going to have. The following day I marked out about six beds and I covered the rest of the plot with heavy cardboard that a local shop gave me. I then started digging. I spent most nights and the weekend digging the six beds, I piled the weeds and stones that came out of them up at the front with the rubbish from the first night. As I cleared the beds I put cardboard on them. The first bed I had cleared, I chanced sowing some peas, carrots and beetroot in. The rest of the beds were ready by mid/end July and everything in the modules were popped in then (I have since learned about rotation but for that year everything just went in together). I then took a breather!! I spent the next couple of weeks just weeding the six beds, strumming I between them and disposing of the rubbish pile and the weed and rock pile. I had a weeks holidays in August so I took John's book and a pen and paper with me and sat working out what I was going to grow the following year and where it was going to go in the plot. When I came back from holidays I marked the rest of the plot out, got my shed, built my compost bins and started digging beds for fruit and my over wintering onions and garlic. As each bed was dug I covered it with the cardboard. In the Autumn I popped my onion sets and garlic in and I also bought bare root fruit bushes which went in.
The only thing that I got nothing off were the peas as they got mildew and I didn't get much off the purple sprouting broc as it was in the wrong place and I had to pull it up the next year to make way for the crop that was going into that bed.
My big bit of advice - don't overdo it. Using the modules to start stuff off will buy you a good 3 to 4 weeks.
Good luck