Hello,
starlog wrote:
set protocols osspf area 0.0.0.0 interface ge-0/0/1 priority200
set protocols osspf area 0.0.0.0 interface ge-1/0/39 priority 200
Leaving the xe- interface at the default 128 value.
This only sets the DR priority and does not affect the interface cost/metric.
Just do what Ashvin told You and/or read the online docs and You should be golden 
HTH
Thx
Alex