Explanation:

There are different ways to prepare the data in Tableau Prep, but one possible answer is:
Answer area:
Join the tables.
Aggregate the data by Sales Team.
Add the following filter to the Employees table: Sale Team - Team Alpha.
To analyze sales trends over time for every sales team, you need to combine the data from the Orders and Employees tables. You can do this by joining the tables on the Rep ID column, which is a common identifier for both tables. This will create a single table with all the columns from both tables. Next, you need to aggregate the data by Sales Team, which is the level of analysis you want. You can do this by grouping the data by the Sales Team column and applying an aggregation function (such as sum, average, count, etc.) to the other columns that you want to measure (such as Total Amount, Rep Tenure, etc.). This will create a summary table with one row for each sales team and the aggregated values for the other columns. Finally, you need to filter the data to focus on a specific sales team, such as Team Alpha. You can do this by adding a filter to the Employees table and selecting only the rows where Sales Team equals Team Alpha. This will remove the rows for other sales teams and keep only the data for Team Alpha.
References:
[Tableau Certified Data Analyst Exam Prep Guide], page 9, section "Preparing Data"
[Tableau Help: Join Your Data]
[Tableau Help: Aggregate Your Data]
[Tableau Help: Filter Your Data]