Hi there and welcome
Not too bad is my first thought
Dig up those spuds (they might be useable) for two reasons:
1. They will spring into life next Spring
2. They may well be infected with blight or another disease, which you won't want to perpetuate
Make sure you remember where they have been planted, so that you avoid planting potatoes in the same spot for a couple of years or so
Dig out as many of the larger perennial weeds as you can, as these will just get bigger!
Then sit back and draw up a plan for your plot, that includes answers to these questions
1. Are you having beds with paths, or traditional rows?
2. Will you have a shed? A polytunnel or greenhouse?
3. Are you going to grow fruit as well as veg? Will the fruit be in a fruit cage? Will you have fruit trees?
4. Will you also grow flowers?
5. Are you going to have a seating area/children's play area?
6. Where will your compost bins go?
and then decide what veg to grow - ir what you will eat- and buy seeds/order seed potatoes/onion sets etc to be ready as soon as the Spring arrives
Oh yes, and keep an eye on this forum as then you'll know when people plant what in your area (roughly anyway)
Hope that helps
and best of all: enjoy yourself
You can't do everything on day one!!!!