Zend certified PHP/Magento developer

Setting up home network with 2 routers

I have a router that I got from my ISP (Technicolor GCA4233DE) and my own router (Asus DSL-AC87VG) and I’m trying to setup my network in a way that all devices can see each other.

The ISP router has only one PC connected to it right now and the WiFi is disabled.
The Asus router is connected to the ISP’s via the WAN port on it (lan to wan) and configured as a bridge/access point.
See diagram here

Now the problem: The devices connected to the Asus router can reach the ISP router and PC but the PC can’t reach anything.
My understanding is that I need to reroute the Asus IP (for example 192.168.0.110) to the other devices but I don’t know how.

What option should I be looking for on the ISP’s router?