Transit Gateway policy table

Dear Team - As per https://aws.amazon.com/blogs/networking-and-content-delivery/achieving-traffic-segmentation-in-multi-aws-region-environments-using-aws-transit-gateway-and-aws-cloud-wan/,

To achieve dynamic routing over the Cloud WAN – Transit Gateway peering, you must associate a Transit Gateway policy table to the Transit Gateway’s peering attachment. The table contains policy rules for matching network traffic by policy attributes, and then it maps the traffic that matches the rule to a target route table. When you associate the policy table with the attachment, it populates the table automatically with the policy rules.

i dont see any option to see or configure the matching policy rule in policy table. is this policy table is really configurable ? i can see routes are rightly populated in TGW/CWAN segment but still wondering what this Transit Gateway policy table is doing which we can see ? wondering why i dont need two of the policy table for two diff route table from TGW ?