For home office expenses there are three fields: GST, HST and exempt.

You would put it in either the GST or the HST column depending on what tax you paid.

HST has GST built in, so if you paid HST on an expense, then you would enter it in the HST Taxable column.

If I pay GST and PST on an expense (my phone bill), do I put the total I paid BEFORE tax in each of the GST and PST columns (same amount in each column) or the amount I paid AFTER the specific tax in each column???

@mjccmack You enter the full amount that you paid (including sales tax) in the GST column. There is no PST column.