networking - Connect Ethernet and WiFi networks together in the same computer

I have a wifi home network, And a laptop "D", that doesn't have wifi connectivity. I can plug it in to "W", one of wifi enabled computers via an Ethernet cable and now it's possible to get Internet connectivity using Windows Internet connection Sharing Service.

But according to my knowledge, the main wireless router doesn't know that this D's existence. Right?

In D, the OS is Debian and I added a route through W's Ethernet network IP. Then D can connect to other computers in the wifi network.

My problem is that how do I let other computers in the wifi network to connect to D? Is that possible?

I tried to add a route to the W's Ethernet IP in router's routing table. But its not reachable of cause.

The answer as above in the comments all relates to correct routing of the traffic.

The ZTE w300 has its IP address. Laptop W with two IP addresses one for WiFi and One for Ethernet. Laptop D with one IP address for Ethernet.

The static route on the ZTE w300 should state "Route Laptop-D-Ehternet-IP Mask x.x.x.x Laptop-W-WiFi-IP" which will push traffic from Router to Laptop W when it gets a request for Laptop D.

Now when this traffic hits Laptop W it needs another route to say "Route Laptop-D-Ehternet-IP Mask x.x.x.x Laptop-W-Ethernet-IP" this basically says you want Laptop D you can find him down that Ethernet Cable. One issue you will have is DNS so test with IP.