If I use the clip will I have to pay the composer of the music clip? Am I considered the broadcaster?

Broadcasters are the TV stations, radio stations, NetFlix, etc. They are the ones responsible for paying performance fees to the Performing Rights Societies (PRS). Then the PRS pay the composers. Broadcasters always pay a regular fees to the PRS’s. You just need to report what music was used, so the composers can get their slice of that fee. The music license purchaser (you) are never responsible for making any payments to a PRS.