pd has sound advise.
Dad started a 1/8 acre or so of Black Raspberries from starts(got from a friend(all day process, maybe more, can't remember)) we transplanted.
He mowed the area, spread manure in rows then tilled just the planting rows(It made for easier planting).
The first couple years he mowed between the rows. After that the grass was allowed to grow unchecked. We would(two year cycle) mow new paths in the patch to re-establish a walk path and mulch the old canes at the same time. This technique made for a neat rotating cycle that allowed new growth to always be in fresh ground.
Later he determined the initial mowing and tilling was likely not necessary, as the birds created new berry patches in weeds and tree lines.
Personally, I would at least mow the site short(till if growing by seed).
The manure was on the same 2 year cycle as the mowing.
If you have the space a three part cycle would be easy to maintain, 4 foot wide strip/row, as the canes grow they get bent over into the next 4 foot row and root in that section, the next year the canes get bent over into the 3rd 4 foot section and you mow the first row end of 2nd year, this technique may require a year or so to get a good crop started. This is a very clean and easy process with new canes always moving in the same direction and a free row to stand in for picking.