Hi @DiviB,
Welcome to the Bunnings Workshop community and thank you for your question.
You could use either a paint sprayer or a roller and brushes to apply your paint and primer.
It is easier to get a smoother finish with a paint sprayer, but if you use a high-quality foam roller, apply even coats and lay off your paint by rolling back over it in the same direction, you will get a comparable finish.
You just need to make sure that if you are using a sprayer that you thin the paint and primer so that it doesn't clog up the paint sprayer. Your paint sprayer will have instructions on what you need to do to thin out your paint.
Check out How To Paint Tiles for some guidance.
If you have any further questions, please don't hesitate to ask.
Jacob
