Short visits are better than long and infrequent visits
Cover ground with black garden fabric (no carpets allowed).
Mark out plot with paths and beds.
Dig and plant an initially plant an area manageable to you, hoeing regularly.
When under control, dig and plant another area.
Good starter plants are potatoes, runner beans, courgettes, marrows, sprouts, cabbage, sweetcorn and rhubarb.
You can download a Woodley Town Council/Allotments Committee jointly prepared Welcome Pack, which covers many areas for new people taking on an allotment.