kentlass, it's a bit early to be sowing seeds yet - you need to wait for it to get a bit warmer.
I'd suggest having a think about what you want to grow and what facilities you have. For instance if you want to grow more tender plants such as tomatoes, melons, peppers, aubergines etc you'll need to provide them with some protection- they are usually grown under glass and will need to be sown inside and grown on. More hardy veg, such as cauliflowers & cabbages can generally be direct sown. Salad crops are very easy to grow in the summer (when the soil is warm) and will happily grow outside. Carrots are more challenging - they'll need good (fine / no stones / deep bed) soil that's not been manured and will need protection from carrot fly. Beans are very very easy to grow and highly productive -you just have to protect the germinating seeds from hungry mice - again grow inside, then plant out AFTER all chance of frost has gone (prob end May to be safe).
There are so many things - why don't you have a think about what you like to eat and we'll be happy to give you some advice - let us know what your soil is like (clay vs loam, acid vs neutral) and how shady / sunny your garden is.