Not able to find Build Pipeline Trigger as soon as new feature request is created in azure devops repository

[severity:It’s more difficult to complete my work]
I am trying to trigger the build pipeline automatically after new feature request created in repositories . I tried to set the trigger at pipeline level and added the branch filters there , But its only will work when any new commit/changes found in existing branch , that trigger is not working for new branch creation.

Please help me out here

I have added here branch filter , my branch name is

feature/14june_01

(inside feature folder / branch name is 14june_01)

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Thanks I found this Azure Training Program really helpful.