I looked at that page earlier and didn’t see anything specific but I looked closer and saw that the setting is under Custom Scans. Seemed to be easier to find in older versions.
To edit your custom scan settings, go to Protection ▸ Virus Scans ▸ Custom scans, then hover your cursor over the scan name and click … More (three dots) ▸ Settings.
Maybe the support page could be amended to clearly state how to adjust scan schedule settings?