You have a pivot table in Excel. The months and weekday names are appearing alphabetically instead of in calendar sequence. This happens when your pivot table is based on external data or the data model.
There are two solutions. This video prefers using the Custom Sort Order option. This takes 8 clicks to fix the months and 8 clicks to fix weekdays.
If your Pivot Table Slicers are in the wrong sequence, then you should use the Data Model setting to sort one column by another column.