PowerBI Report

I have a PowerBI project I need help on. This is likely relatively easy but I'm not super familiar with DAX. I have a SQL Server database direct connection. In one table I have Invoices that were entered by a SalesRep and the associated date of the invoices.

I need to create a report that has details on SalesRep performance by week. Also, have a column that details a comparison of the same week last year. The company wants to create sales goals for their reps based on previous performance. Any additional reporting you think could help achieve this goal would be appreciated. Probably some Overall totals and the ability to adjust date ranges for report viewing.