Deep Scrub, wax, buff 46,000 sq ft. Client supplies the wax

In all my years of office management and bookkeeping in the trades, I have seen estimating make or break someone. You have written half a line of nothing and want someone else to ask you all the right questions, of which there are at least 20, if not twice that. That doesn't look too good for your career.

Design an estimating form, and go back to the place, ask more questions, and fill in all the blanks. YOU are the only one who can envision a 12 x 12 area of what must be done, and then multiply it by the full size, and add a good amount for unforeseen expenses and expectations. Is the power on in the whole place? Any debris in the way? Are any tiles broken? Are any too far worn down, period? Is the floor even? Can you demand 1/3 in advance for materials, and 1/3 halfway through, and 1/3 at the end, on the spot or within 10 business days?
Then go back home and design a bid form, and impress them with details. Brand name of products. Promise of start and stop dates. And so on.

If this boggles you, go out and get a job for someone else.