I have install erpnext through virtual image but how we restore our backup

i have install erpnext through virtual image but how we restore our backup files.I have backup on drop box which i download but how to restore in local installation in virtual images

What version of erpnext have you installed.

In v4 follow this link https://github.com/frappe/erpnext/wiki/Restoring-From-ERPNext-Backup#version-4-frappe-bench

In v5, the command is bit different and use the commands

bench restore [Path to DB SQL File]

If it fails on the test environment use the below command but only on test server:

bench --force restore [Path to DB SQL File]

when i am doing then no restore command is coming .i have chaged directory
to frappe-bench then do the same command as you suggested

i am using version 4.11 and when i run command 2nd bech frappe
localhost:8080 --latest then following error shot is coming

type error :connect() argument 2 must be string ,not none

can anyone please help me on this

Which VM have you downloaded? V4 or V5?