Installing tile outside
Depending on the condition of your concrete patio, I would use something like LevelQuik to make sure the concrete surface is nice and level before putting those tiles down. Concrete patios often have slight dips/rises that are hard to see, but most hard tiles are very unforgiving with variances like that. 

After leveling you want to put an isolation barrier on top of that. If your concrete expands over time, your floor will "float" on top instead of splitting apart.

If you have a smooth patio (not broomed or roughed up), you might have a hard time getting anything to stick.

You need to make sure you have non-porous tiles, they may be called “frost-free,” “vitreous,” “impervious” or “freeze-thaw stable,” but whatever the label, make sure it’s warranted by the manufacturer to withstand freezing. Again, water is your enemy.

You do need to make sure you get outdoor quality mortar and grouts, and make sure all seals and grout lines are densely packed/caulked. You want that whole floor as water tight as possible.

If you live in a rather cold (freezing) climate, its not recommended to do any kind of ceramic tile, any water that gets under there will just tear it up with ice expansion over the years.