Did you download your Mac version from here:
If so, please see: https://docs.moodle.org/35/en/Installation_Package_for_OS_X
*** AND ***
IF you installed on a laptop that uses DHCP for connections to a TCP/IP network and is frequently, shutdown and taken to another location ... like home ... and are thinking about trying to use MAMP for outside internet access, please think again. The IP address of your laptop isn't static ... permanently assigned IP address.
Besides that, think there is a limitation as to the number of users that could connect to the Moodle at one time ... laptop isn't a server class machine.
MAMP is used for development of Moodle content. To serve Moodle to the internet, one needs a true internet server - remotely hosted by some provider.
In anticipation of the next question ... No ... I don't have recommendations for which hosting provider would be best for Moodle. Too many factors for 'free' consulting. Suggest Googling and shop around.
'spirit of sharing', Ken