Disabling manual cell execution can be useful setting to use while working on some analysis.
Cells in Count run automatically when a change to a cell, or an upstream cell, is made. For analysis that you know will involve a lot of edits to cells, consider turning this automation off to reduce the number of queries going to your database until you have completed your edits.
It is possible to control this setting across your whole canvas (accessed in the Design panel when nothing is selected on your canvas):
or for specific cells only (accessed from this menu when your cell is selected):
The following video demonstrates this functionality further.