Hello Gardening Experts!

I am new to gardening and am aiming to try and turn my garden into a little more ecologically friendly. So I have a couple of questions:

1) I am looking for the contaption I can put food waste into and it naturally degrades into the garden soil, does anyone know what I am talking about?
2) I am looking at getting a small green house and want to grow some 'easy' veg/fruit, please can you give me some suggestions as to what and when I should be planting? I am trying to get my kids involved as much as I can

Thanks in advance

RM