Serbinski Accounting Firms

Would this mean that I pay double taxes? I don't want to find that out at the end of the year.

I am Canadian with GC and am planning on moving back to Canada very soon. Not planning on giving up the GC. I have been offered a job a US company and will be paid in US dollars. I'm not sure how they're setting me up as an employee and getting me benefits. I have not signed any forms such as W9s or...