If the card is setup correctly, CHDK will load automatically when the SD card is locked. Do you see the CHDK logo appear briefly on you LCD screen at boot?
If no logo, please post the
sticklog.txt file that should have been created in the folder where you installed STICK when you ran STICK. Please post that as an attachment here.
The SX710 is a DIGIC6 camera. For various technical reason related to random performance glitches, the firmware update method of loading CHDK on those cameras is not available.
Hint : from the
Stick Web page :
Recent versions of OSX (Mountain Lion and later) require root access to make changes to cards. As a result, STICK will fail with a "permission refused" message unless it has root access. To run STICK under Mountain Lion, Mavericks, Yosemite, El Capitan or later versions, use the stickML.command script. Double-clicking the script will bring up a terminal window and sudo will ask you to type your logon password so STICK can get root access. STICK will run when you press return.