Email capture web page for business supplying WIFI MAILCHIMP

We are supplying free WIFI to our customers.

Our WIFI system permits us to forward customers to a URL once connected to the free WIFI.

We would like to grab their email address as well as automatically import it into our mailchimp list using their API

For instance

a) Customer logs onto the free WIFI
b) Customer is taken to a url (the page we're asking you to build) as well as asked for their name &, email address
c) Once the customer has completed the email address will automatically be introduced to our email list with Mailchimp (the list will just grow daily with new customer email address)
d) On submission, the customer is forwarded to another URL supplied by us.
e) If the customer returns to usage the WIFI on the same device, the page you are creating will detect so (via cookies??) as well as not ask them to re-enter their details

It's very significant that

a) The customer doesn't have to complete the form every time they use the free WIFI, can this be avoided by the coding on the page? Cookies etc?

Desired Skills are HTML, PHP, MailChimp