Hi Elise,
In order to enable the wireless settings for the MX you can navigate to
Security & SD-WAN/Teleworker Gateway > Configure > Wireless settings and toggle the SSID status to Enabled.
I'm attaching the article from our knowledge base over our MX and Z series wireless settings below for more detailed instructions:
https://documentation.meraki.com/MX/Wireless/MX_and_Z-Series_Wireless_Settings
Best,
Alex