I want to enable Cache on NTH merging ( 2 lan lines )

Hey ,

I’m working on mikrotik v3

with 2 input lines on NTH merge
the 2 inputs are being connected via pppoe with the routers ( routers on Bridge mode )
and using Hotspot for users login

well , that’s the whole story , need to add The Cache feature for the system

what necessary steps, rules to do it ?

Thanks