To connect a Tableau workbook to a dataset in a Microsoft Excel spreadsheet, you need to select New Data Source from the Data menu. This will open the Connect pane, where you can choose Microsoft Excel as your data source and browse for your spreadsheet file. You can then drag and drop your sheets or tables to join or union them in the data source page. References:
https://help.tableau.com/current/pro/desktop/en-us/connect_basic.htm
https://help.tableau.com/current/pro/desktop/en-us/connect_excel.htm
When connecting to a dataset in Tableau Desktop, you would go to the 'Data' menu and select 'New Data Source'. This allows you to connect to various types of data sources, including Microsoft Excel spreadsheets, where you can then select the specific file you wish to connect to.

Extensions in Tableau are web-based programs that can interact with dashboards. To add a button that allows users to export the dashboard as an image, you would use an Extension object. This could be a custom extension designed to trigger the download of the dashboard view as an image.

To combine the two tables that contain data about books in a library and ensure that all the data is retained, you should use a full outer join. A full outer join is a type of join that returns all rows from both tables, regardless of whether there is a match or not. If there is no match, null values are filled in for the missing fields.
To perform a full outer join, you need to do the following steps:
Connect to both tables as your data sources in Tableau. You can use either live or extract connections.
Drag one table to the canvas and drop it on top of another table. This will create a join between them based on a common field.
Click on the join icon between the tables and select Full Outer Join from the drop-down list. This will change the join type to full outer join and show all rows from both tables.
Optionally, you can add or remove join clauses by clicking on Add or Remove buttons next to each clause. You can also change or rename fields by clicking on them.
The other types of joins are not correct for this scenario. An inner join returns only the rows that have a match in both tables, which will exclude any books that are missing from either table. A left join returns all rows from the left table and only the matching rows from the right table, which will exclude any books that are only in the right table. A right join returns all rows from the right table and only the matching rows from the left table, which will exclude any books that are only in the left table. Reference: https://help.tableau.com/current/pro/desktop/en-us/joining_tables.htm https://help.tableau.com/current/pro/desktop/en-us/join_types.htm

check the steps below in explanation.
Explanation:
To filter the table to show the members of the Top10 set and the Bottom10 set, you need to do the following steps:
* Open the link to Book1 found on the desktop. This will open the Tableau workbook that contains the Disciplines worksheet.
* Click on the Disciplines tab at the bottom of the workbook to open the worksheet. You will see a table that shows the disciplines, sales, and profit for each salesperson.
* Click on the drop-down arrow next to Salesperson on the Filters shelf. This will open a menu that allows you to filter by different criteria.
* Select Set from the menu. This will show you the sets that are available for the Salesperson field. You will see Top10 and Bottom10 as two sets that have been created based on the sales ranking.
* Check the boxes next to Top10 and Bottom10. This will filter the table to show only the members of these two sets. You can also click on All to deselect all other values.
* Click OK to apply the filter. You will see that the table now shows 20 rows, 10 for each set.
References: https://help.tableau.com/current/pro/desktop/en-us/sets.htm https://help.tableau.com/current/pro/desktop/en-us/filtering.htm