A little bit confused, what is the exact way to open/allow everything from one Internet IP to the server behind RB750G router?

Let's say:

The Internet IP is "InterIP"
RB750G WAN IP is "WANIP"
The server IP is "SerIP"

What I did as follows:

Winbox---IP---Firewall---Filter Rules:
chain: forward
src. address: InterIP
dst. address: WANIP
action, accept

Winbox---IP---Firewall---NAT:
chain: dstnat
src. address: InterIP
dst. address: WANIP
action: dstnat
to addresses: SerIP

Really appreciate it if someone can clarify.

If the server IP is a private ip (eg: 192.168.X.X, 10.X.X.X, 172.X.X.X), than this is the correct way.

Thank you very much for your verification. I am a little bit confused with port and IP. If we specify source IP and destination IP without specific ports, which means everything is open between these two IPs?