How do I affix a button to the edge of page/window?

I would like to add directional buttons (i.e. linked to other Unbounce pages) to the left edge and right edge of a LP. Is there a way of keeping them affixed to the edge?

I want them to remain visible if the page is resized/widened.

Thanks in advance.

Todd

p.s. Really appreciate the recent updates to the UI. Great work Unbounce. Thx.