tending to a virgin plot

hello

i have been fortunate enough to get one of 30 new allotments up in north wales.

i wont be getting the keys till the end of september and by then it will be a bit late to grow stuff but as this is a green field we are having its perfect timing to prep the lant for the spring.

i am going to rotovate the land and ph test the soil but im a bit unclear on whats the best type of manure to put on. i have read various articles etc about "green manures" and wanted a few opinions on them. are they any good? are they any better than the normal cow manure?

also i assume i will have to cover the newly rotovated land if i dont cover it in a green manure?

im also trying to plann out what to grow where. is there any free software around that will automaticly space the veg out? i.e i want something that will tell me that my pototo rows will need x amount of space? ive done some rough plans of what i wnat where but i have little knowlage about spacing things out.

thank you all.