how to combine many spreadsheets into one big one?

I have also attached a workook with how i would like it to look.
I would have 2 work sheets, one called Customer and One called Hardware.
And then a 3rd worksheet that would show what customer has what system.
I was hoping that I could have some sort of dropdown menu for the 3rd sheet.
I would select the Clients Name, and then the associated client information would populate the relevant fields, and then I would select a HASP Key and the associated hardware info would auto populate.