Welcome to the Bunnings Workshop community @JohnN3. It's fantastic to have you join us, and many thanks for your question.
You might like to provide a little more information about what the battens will be used for, so our members have a better idea of fixing methods to suggest.
The general process would be to drill holes in the bricks with a masonry drill bit where you would like the batten fixed. You can then tap plastic wall plugs into those holes. You'll then drill corresponding holes in the timber and fix timber screws through the batten into the plastic plugs.
Alternatively, and depending on the purpose of the battens, you could glue them in place with a construction adhesive. However, the screw and plug method is stronger.
I look forward to hearing more about your project and please let me know if you have questions.