Written ledgers

Filing cabinets

Hard disk storage

Laptops

Cloud storage

Cardboard boxes of invoices

Click every little button (e.g. "The first menu item takes you to the home page. The second button takes you to the contact us page. The third...").

Think about what a user of the system wants to accomplish when using the system, and show that. 

Point out every little feature (e.g. "In the top right we have a login button. Next to this is a button for if you forgot your password, and here is a button to sign up").

Ensure you explain all of the validation which happens in the login form, e.g. "Here we will try to enter a password with only lower case letters. Now watch as I type all numbers and it tells me I need to have a letter. Now I'll try a password that is only 4 characters long").

Think of their user journey and show that.

Can they use the software?

Are there any bugs

Does it add value to their business?

Does it behave exactly as they expect?

Is it really what they wanted?

Does it crash?

just the client or their representatives (e.g product owner)

the team and the client

the mentors and the team