I'll throw in my 2 cents: dig up the grass. each shovelful gets turned to the side and I let it dry up a little so as to easily shake out the roots and all. I find it best a few days after rain so that it's not too hard and clotted up, although you don't want it soaked wet either. I shake out all the bermuda very carefully in each clump, must get every bit of bermuda out! :). I put a border of black plastic barrier from Lowes to keep bermuda OUT and I will put anything decorative inside that barrier (bricks or other borders etc).

I will then begin the amending! adding lots of peat humus, some very fine pine bark mulch, any compost handy -mushroom, cotton burr, other, this is all mixed in( I have a smaller garden rototiller just for beds). But everyone's soil is different, but organic organic organic. If I have alfalfa pellets I'll mix that in too because the pine bark breaking down will take nitrogen out of the soil etc..

anyway, that's about it. I put in my plants and mulch well with regular pine bark mulch. wallah! :) hope that gives you an idea of my island bed. they keep expanding a few feet each year . ha :)

Deangreen, that is how i did my current 40x4 bed. I too have a small rototiller. I used cedar logs from our property as a border. I have on hand peat moss and some of my own compost but will have to buy others: fine pine mulch, alfalfa pellets. Thanks for your system.