How to add static route to another network

Question

Below is my network topology, with an example device in network A:

I configured a static route on Network A as follows: 
 10.1.2.0/24, next hop, 192.168.1.251 
 I want to do the same in reverse from the UTM (10.1.1.0/24, next hop, 192.168.1.10). How do I add this static route? 
 Also, is there anything else that I need to add to make sure I can see devices on Network A from Network B?

Ol Deda · Answer

In UTM create host (192.168.1.10) and use it as Gateway when you create Static Route The Network 10.1.1.0/24 must be created in UTM aslo Ad the rules in Firewall to allow such traffic Internal > any > lan10 (10.1.1.0/24 > Allow The problem must be the configuration of the UBNT. It has to allow these traffic too.