New Allotment (Advice needed please)

I have just got a new allotment plot and I'm really excited about growing vegetables on it! However I know I have got a lot of work to do first in terms of getting the soil right. The soil is thick clay with lots of twigs and stones and bits in which I need to get rid of.

My question is what do I need to do to improve the soil. I haven't done a thing on it yet as I'm an absolute newbie and would like to get some advice before I start.

Any advice would be very gratefully appreciated!

There's no weeds at all.

It might just mean that the plot has been cleared, rather than anything sinister!

If the soil sticks to your boots, keep off.

Otherwise, as I said, remove the worst bits in the soil and get planning 

Spuds and onions should be in asap.  Other stuff can take a bit longer.

Have a think what veg you like to eat. Potatoes are good at supressing weeds, so you don't have to keep weeding that area and have more time to work on the other crops. I would not worry too much about improving the soil until you know what will grow...but if you find a good source of manure don't say no to it.