GL-MT300N-V2 block internet to LAN


I have GL-MT300N v2 and I would like please to ask if there is a firewall rule I can apply in which I can block internet on all the LAN port?

Basically I am connecting it to a switch to act as a router with static ip on it so I can VPN to this remote location however I dont wish to pass internet of this static ip to all machine on the LAN and in the same time would be able to VPN and be on that same LAN from outside

Your help is highly appreciate it

Any help with this is highly appreciated

Thanks in advance