I have a network like this:
Huawai modem for ISP has IP 192.168.18.1.
a mobile phone A connects using WiFi and gets IP 192.168.18.5
then from Ethernet 2, connect it with a cable to the Mikrotik B router with WAN IP 192.168.18.106.
This Mikrotik B router has LAN IP 10.10.10.1. and distributed to computer C with IP 10.10.10.12.
I want mobile phone A with IP 192.168.18.5 to be able to ping computer C with IP 10.10.10.12.
Mobile phone A can ping the router 10.10.10.1.
Why can't ping to computer C with IP 10.10.10.12.
What should be set in the firewall and route?

You need to add a static route on the Huawei router for the 10.10.10.0/24 network

You need to add a static route on the Huawei router for the 10.10.10.0/24 network

thank you, I did it like that and it worked.