In article .com,
wrote:

Is this a doable project by myself?

Other suggestions have been pretty reasonable. However, if you'd like to
get it level before the building goes up, here's the low tech, hard
work, no particularly expensive tools to buy method. With slight
modification this method can also be used to make precise slopes (around
the building, usually, sloping away to carry water away).

Get a bunch of stakes. Pound them into the ground on a grid. Use some
form of level to mark them all at a convenient height (perhaps 2-3 feet
above your desired grade). A water level is cheap, a laser level is
probably sitting aound some friend or relation's house not doing
anything, though some of those are not that good, so the water level
(dscussed in greater detail in other replies) may be the method of
choice.

Now, run strings on the mark from post to post. Mark the handle of a
steel landscape rake at the distance your string is above your desired
grade. Set the rake on the ground, bend down, and look from the rake
across the strings. With multiple strings, they form a plane, which you
can reference your eye to and figure out if a particular spot (which
need not be right next to a string) is low, high, or correct. Rake until
all are correct.

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