On the Check Point side, you would need to ensure that your encryption domain includes network/IP ranges with clients you want to be able to communicate through the VPN (i.e. be encrypted).
That means, using your diagram, 218.1.76.0/24 would need to be included in your encryption domain.
The other end would need to have its VPN configured to expect this subnet from your gateway (or use NAT).
The relevant clients would need to have a route to the relevant networks that traverses the Check Point gateway.
The gateway would also need to know how to communicate with the sales computers.
This is all basic routing configuration, the specifics of which are environment specific.