Good Evening

Good evening
I need to create a vpn with a microtik connected only in LAn mode to an existing network.
The existing network already has the internet.
The PCs on the network must be able to see the VPN to which the microtik connects and vice versa
It's possible?
My vpn must work on both sides.
It's possible?

Here is a scheme.

Yes it is possible...

How??