As you have the contacts in form of
.vcf file(s), you can use the Contacts app's native import functionality:
- Start the contacts app
- Tap the "3-dot-menu" (top-right of the screen)
- From the drop-down menu that opens, chose "import/export"¹
- On the next page, chose "Import from SD card"²
- A file browser should open and let you chose the file to import. Pick your
- Now your contacts should be imported. If you have multiple files, repeat above steps.
Visualisation of the process (click image for larger variant)
¹ if there is no "import/export" directly in that menu, check the sub-menus – e.g. Manage contacts or Settings
² might be phrased slightly different, like "import from internal storage"