How large is large ie what area will you cultivate?
If you plough, then eventually many of the grasses etc will reappear. On a farm scale, the ground is sprayed first and all vegetation allowed to die down before ploughing. As this is for you to grow vegetables on I can't imagine you will be wanting to cover the whole area with poisons. You could cover with large tarpaulins for a year before ploughing to kill off the vegetation, but that would mean postponing starting your garden for a whole year.
On a garden scale, the usual thing is to lift off the turf (you can probably hire a machine for that). This is not wasted, as you stack the turves upside down and cover the heap. In a year or two you have some wonderful loamy topsoil to spread back onto your garden.
Once you have cleared the ground, a PTO mounted rotavator passed a couple of times over the area will prepare it for planting, whilst not disturbing the soil structure too much. If your soil is not deep, then ploughing simply brings subsoil to the top, which you don't want. The rotavator can be used to work in manure too, and will be invaluable in future years. This depends on the area you will be cultivating of course - a wheeled garden sized rotavator might do, but does not cultivate so regularly or deeply.