Explanation
Setting the default value of the Lead Source field to Trade Show' is the best approach to improve data integrity for the Lead Source field. A default value is a value that is automatically populated in a field when a new record is created, unless the user enters a different value. Setting the default value to Trade Show' would save the sales reps time and ensure that most of the leads have the correct value for the Lead Source field.
Creating a validation rule requiring the Lead Source field to equal Trade Show' would not work, because it would prevent the user from entering any other value, such as Web, Phone, or Referral, which may not be accurate for all leads. Making an assignment rule named Trade Show' to only assign leads to sales reps would not work, because it would not affect the Lead Source field, and it would not allow the user to assign leads based on other criteria, such as territory, industry, or product.

Explanation
The best way to create a field that shows the amount as described in the question is to use a bucket field off of Amount. A bucket field lets you group report values into categories without creating a formula or a custom field2. You can create a bucket field for any numeric, picklist, or text field in a report.

The way that the associate can locate all the reports in a single location from the Report object is to click on All Folders and use the search bar. All Folders is a menu that shows all the report and dashboard folders that the associate has access to. The associate can search for the current month's folder by entering its name or keyword in the search bar and then select it to view all the reports in that folder. Using the Global search bar or clicking on All Reports and using the search bar are not as efficient and accurate as using the All Folders menu, because they will return results from all the reports and folders, not just the current month's folder.

Explanation
The switches that the associate should toggle to only show the Record Count are Row Counts and Grand Total.
Row Counts is a switch that shows the number of rows in the report, which is the same as the number of records. Grand Total is a switch that shows the sum, average, minimum, maximum, or other aggregate functions of a numeric field in the report. By toggling these two switches on and the other two switches off, the associate can see the Record Count and the Grand Total of the report, without seeing the individual records or the subtotals. Subtotals and Detail Rows are switches that show the breakdown and the details of the records in the report, which are not needed for the Record Count.

Explanation
Salesforce Help is where the associate should go to understand the differences between the data types.
Salesforce Help is a resource that provides documentation, guides, videos, and support for Salesforce users who need assistance with using or troubleshooting Salesforce products and features. Salesforce Help has a section called Data Types that explains the characteristics and use cases of each data type, such as text, number, date, picklist, checkbox, and so on. Customer Support is a service that provides technical support and assistance for Salesforce users who encounter issues or errors with Salesforce products and features. Customer Support is not a resource that explains the differences between the data types, but rather a resource that helps resolve problems or incidents. App Launcher is a feature that allows the user to access all the apps and objects in Salesforce, such as Sales, Service, Marketing, and so on. App Launcher is not a resource that explains the differences between the data types, but rather a feature that helps navigate the user interface.