Selecting Help > Libre Office Help > Search tab > "Autocalculate"
"To access this command...
Choose Tools - Cell Contents - AutoCalculate"
However, there is no Cell Contents entry on the Tools menu.
The help text should say:
"Choose Data - Calculate - Autocalculate"
I suspect the autocalculate menu has been moved since a previous version.
also gives the same incorrect information.
However, it is not clear (to me) how to determine what version of Calc the Help Web site refers to, or how to get help for a specific version.
Adolfo Jayme Barrientos committed a patch related to this issue.
It has been pushed to "master":
tdf#99715 AutoCalculate has been moved to the Data menu