Need some help with this database assumptions problem:

Use the business information provided, determine the size of the new database. List what you will need to do to ensure the new database can accommodate the data described below. Do not use page sizes in your calculations. Use the row size and number of rows.

$80\%$ of the data for the database is going to be broken up into three main tables: products, customers, and invoices.

$$ There will be $1,000$ products in the products table with each row being $5,000$ characters. Each character is $2$ bytes.

$$ There will be $1$ million customers in the customer table with each row being $10,000$ characters. Each character is $2$ bytes. The company plans to expand their customer base by $10\%$ each year.

$$ Invoices will likely include $5$ products. The invoice table includes a primary key, invoice key, product key, and customer key. There are four columns$/$keys$.$ Assume each key is $20$ bytes in length.

$$ A customer will be invoiced $10$ times per year.

$$ Reporting requires there to be an index on invoices for sorting by products. Indexes are $10$ to $20$ bytes in size for each column value indexed.

$$ Assume the database will be used for $10$ years when determining your estimate.

$$ System requires $5000$ concurrent users

I have determined the products and customers in the table I have, but could use a second opinion. I am also hoping to understand the invoices requirement better.