An installation generally involves several independent files.
Immigration
Visa / exemption / TRC.
Residence
Declaration of your accommodation.
Work
Work permit or exemption.
Bank
Opening an account and proof of residence.
Phone
Registered Vietnamese SIM.
Taxation
Determination of your tax situation.
Health
Insurance and medical coverage.
Housing
Rental contract and declaration.
Therefore, you should think of the installation as a set of procedures, not just a simple visa application.