Help with aligning footers in pages 09

I need to put in 3 footers in to my document. (1 left-aligned, 1 centred and 1 right-aligned)

I type in something as left-aligned, then I want to type something centred, so I click centred, but what I just typed goes there, not just the cursor.

Please can you help?

How do I sort this?

Thank you.