What you're trying to do is fairly basic. It's not clear what part of it you're asking for help on.
Perhaps you could post a copy of the tentative sheet you already have (not an image; an actual copy of the excel file), putting it on OneDrive or GoogleDrive with a link here that grants edit access. And give us a bit more of an idea of what you envision by "then add back into inventory when it is replaced by typing a word or letter in the received column"--
I've attached a very basic example of what can be done. It looks like this, and the formula in column E is
=IF(ISBLANK(A3),"",E2-C3+D3)
which leaves the column blank if no date has been entered, but once a date has been entered it
subtracts any entry from "Sold" and adds any entry under "Received"
