Problem with INDEX, MATCH, and a function to count data from a table

I am new to the forums, and this is my first post, so I apologize if I don't come off as clear as I am supposed to. I have been working through a project involving sales and amounts, but have become stuck. I need to find a way to be able to type in a person's name (It needs to work for any name within the table), and be able to have specific information appear in the cells below said name. I'll include the Excel file and my tasks as an attachment to aid clarification. I know how to use MATCH and INDEX in order to pull a name from the table, but the way the table is designed seems to mean I have to use a function that can count in the same formula. I think I am supposed to use DCOUNT, although I also think that may only work with numbers. From what I've been able to come up with so far, my first step would be to count how many times a salesperson's name appears in the column in order to display how many sales they completed, which would be the first bit of information that would be presented when a specific name from the table was typed in. I would also need to show the average billed and the sum of sales. Again, I have included attachments to better explain what I am asking. One is the word document with my instructions (I am on number 8), and the other is the Excel file. Thank you very much for your time.