The general procedures for installing a vanity are as follows:
Make sure the vanity will fit by measuring the area where you plan to instal it.
Comply with the manufacturer's directions when assembling the vanity.
Install water lines and outlet boxes, as well as any other plumbing and electrical connections that are required.
Put the vanity in the chosen spot and, if required, level it with shims.
With the use of mounting brackets or screws, fasten the vanity to the wall.
As directed by the manufacturer, instal the faucet and handles.
Make sure everything is operational by connecting the piping to the vanity and testing the water supply.
As directed by the manufacturer, instal the countertop and sink.
Install any supplementary elements, like a backsplash or a mirror.
I'm hoping these instructions will help you instal your vanity. Please ask any further specific questions if you have any.