Temp work Eligiblities, need some help =/

[FerTito]

Eligibility to apply as you enter Canada

You can apply for a work permit as you enter Canada, but only if you meet the following requirements:

You are from the United States, Greenland or Saint-Pierre-et-Miquelon.
Yes, U.S.

You do not need a medical examination (or you already have a medical certificate).
Not 100% sure what this is.

You do not need a temporary resident visa to visit Canada and your job does not need a labour market opinion from HRSDC (See Jobs that require a work permit but no labour market opinion.)
Is this already having a job, in Canada?