The authority, exactly
This is the fast temporary route, and none of it starts with you. Your employer applies to Service Canada for the labour market impact assessment; only once that is positive do you apply to IRCC for the permit. The permit is employer-specific: it names the employer, the location and the occupation, and you may not work outside what it names. It is not permanent residence, though time worked on it can later count towards the experience the permanent routes ask for.