The easiest installation is to just set the big frog on the ground if you're not worried about it hopping away. :) However, should you wish to secure it, there are a couple options.
There is a stainless steel eye bolt embedded in the bottom, to which you can secure a thin cable lock. This is not totally theft-proof (a cable. can be cut), but would help deter opportunistic or impulsive theft, and is a relatively easy installation.
There are also two embedded stainless steel coupling nuts to which threaded steel rods (which you can purchase from a hardware store) can be screwed into. Then the steel rods can be set into concrete. This is a more laborious but fairly permanent installation, should you desire it.
Installation is NOT included.