Upvote:3
From my search it seems you are flying KL1050 (KLM CityHopper) from Bristol to Amsterdam; then KL0835 (Amsterdam to Changi), and then SQ215 (Changi - Perth).
This is a single ticket; so your baggage should be checked all the way through from Bristol; and you should be picking up your bags in Perth.
At the check-in desk/kiosk - you should get 3 boarding passes; and if you have bags to check you should approach the counter.
As you are transiting through Amsterdam - you may need a transit visa for the Schengen zone.
Have a safe flight - its a long one!