A reference line is used in Tableau to display a line at a constant value or a computed value such as an average, median, minimum, or maximum in a bar chart. In this case, adding a reference line would allow you to show the median, upper quartile, and lower quartile, which corresponds to the changes shown in the bar chart.

To configure the dashboard to ensure that selecting a data point on the map only filters the Detail table, you should select Ignore Actions from the context menu of Sales over time. Ignore Actions is a feature that allows you to exclude a sheet from being affected by any actions on the dashboard, such as filters or highlights. You can select Ignore Actions by right-clicking on a sheet on the dashboard and selecting Ignore Actions from the menu.
In this case, you want to exclude Sales over time from being filtered by the map, so you should select Ignore Actions from its context menu. This will make Sales over time ignore any selections on the map and show all values. The Detail table will still be filtered by the map as usual.
The other options are not correct for this scenario. Removing Dashboard Item will delete Sales over time from the dashboard, which is not what you want. Deselecting Use as Filter will disable the map as a filter for any sheet on the dashboard, which is not what you want. Selecting Deselect will clear any selections on the map, but it will not prevent Sales over time from being filtered by future selections. References: https://help.tableau.
com/current/pro/desktop/en-us/actions.htm https://help.tableau.com/current/pro/desktop/en-us/actions_ignore.
htm
On a Tableau dashboard, when a map is used as a filter, it affects all other sheets in the dashboard by default.
To restrict the filter action to only affect the Detail table and not the 'Sales over time' chart, you would modify the action settings. By selecting "Ignore Actions" from the context menu of the 'Sales over time' chart, it will no longer respond to the filtering action initiated by selecting data points on the map.

The REPLACE function is used to replace all occurrences of a substring within a string with another substring.
In this case, it can be used to remove the semicolons from the Name field by replacing them with an empty string. For example, REPLACE ("John;Doe", ";", "") = "JohnDoe". References: The information is based on the following sources:
String Functions - Tableau
Remove special characters and add a semi colon in a word - Tableau

References: https://help.tableau.com/current/pro/desktop/en-us/dashboards.htm
https://help.tableau.com/current/pro/desktop/en-us/dashboards_create_layouts.htm
https://help.tableau.com/current/pro/desktop/en-us/dashboards_create_watermarks.htm To add a draft watermark to a Tableau dashboard, you would use an image object. You can overlay this image across your dashboard, possibly with some transparency, to achieve the watermark effect without interfering with the readability of the dashboard content.