I did custom database work with VB for MS DOS a graduate of Quick Basic. This was in early 90's.
Two main tools THEN were using Random Access for file Input and Output and Type definitions to define a record.
Type definitions use fixed length strings, so learn or know that too...
So study and practice with those, probably some excellent samples in Wiki.
Probably a ton of new stuff since 90's like accessing standard files such as Excel?
Which I leave to QB64 developer or pro to tell you about.