How to adjust the BGP routing traffic priority?

Device:CCR1036
Software Version:v7.10.2
I want traffic to pass through AS7473 with a higher priority than any other AS(default output via AS174),what should i do ? use output filter to catch “bgp-as-path” and "set bgp-path-prepend x "? How to write a filter to fulfill this requirement?
AS151964.png
Thanks!