Redirect traffic towards one IP to another IP

Hello to everyone…I use pi-hole linux dns server on my network.the problem is that, i can not see all my Clients (total) in pi-hole(you can see in pic.).The IP address of the DNS SERVER is 10.10.10.2 and ip address of clients 192.168.240.0/22.When I look at client ip addresses from dns server,I see a few ip in the form of 10.10.10.3 and 10.10.10.x(same ip blok with dns server).i know to need to write firewall-nat in my main mikrotik (Request future from 192.168.240.0/22 ​​to exit from 10.10.10.2) but i am not sure to how can write it.And i am not sure if i need to write this nat to client router too???
pi hole.png