How to set up a VPN on a router with dd-wrt to access local network resources?

Question

VPN

There is the following network configuration:
TP-LINK TL-WR1043ND router with DD-WRT firmware. The router receives the Internet from Beeline via PPtP.
The Internet is distributed to the local network. Basically, clients connect via Wi-Fi. A file server with OpenMediaVault (OMV) installed is also connected to the router by cable.

Task: set up access to local network resources (namely, at least to file server resources) from anywhere in the world via VPN . The provider gives a "white" address like 11.22.33.44 (this is an example).
Is it possible to configure this using only the router (dd-wrt firmware) or is it necessary to configure the OMV-PPtP plugin?
Tell me how best to do this, otherwise I'm already confused.