Ceramic tiles are unlikely to be frost resistant, however what most people call "ceramic" floor tiles are actually porcelain and will be fine externally, check with your tile supplier as to suitability.

You need to use a powdered adhesive that is suitable for external use and have no voids under the tile so use a "solid bed" trowel, the type with large half round notches.

Also use a suitable external grout.

Jason

Thanks guys!

Would there be anything else I should put on the base?...Or what would I do if its uneven?

K