VPN Client Gateway goes wrong

[Hgott]

Dear community,

I'm desperate with my little VPN project and wanted to get some help here.
I rented an external VPN server and connected it to my Opnsense, it works.

The Opnsense should then act as a gateway, and the other clients should then be able to surf through it.
The OpenVPN connection creates its own interface -> ovpcn1
The clients run over the LAN interface and have their own subnet

ovpcn1 10.139.47.199 (is specified by the provider and changes daily)
Lan 192.168.0.100 (can be adjusted as required)

The settings for the gateway, NAT, rules, port forwarding are back to default.
From here on I have no idea what I should set.
Can you please tell me what I should adjust from here on?

Many thanks in advance

Best regards
Hgott