It's not an idiotic question at all so don't worry. Gardening jargon can get quite confusing at times especially if you're new to it. All-purpose and multi-purpose are basically the same thing and can be used for both veg and flowers when sowing, potting-on, or in pots, troughs, tubs etc. When your veg are ready for planting, dig a hole and sprinkle a bit of blood, fish and bone-meal (BFB) in it then scuffle it in with your fingers. Pop your plants in and give it a good watering. Later on in Summer when your veg have established you'll need to add some more feed and this can also be a bit confusing when you see adverts for various fertilisers to use for potatoes, onions etc. Just use a basic fertiliser such as Growmore or Vitax, and for leafy greens add a few chicken manure pellets as well. I also like to occasionally water them with dilute sea-weed feed because it contains trace elements to give them a little boost now and then. Just looking at growing squash they need a good feed with extra potash so I'd use a tomato fertiliser like Tomorite. Hope this helps.
