How can I find the MAC-address of my laptop?

As usual: it depends! It depends on the operating system of your laptop!
And then: I don't know and it's not my task to know, so please don't ask me.
Nevertheless, here is what may help you:

Can I register my MAC-address automatically?

Yes, you can. Please fill out our registration form

How can I start a DHCP-client on my private laptop?

As usual: it depends! It depends on the operating system of your laptop!
And then: I don't know and it's not my task to know, so please don't ask me.
Nevertheless, here is what may help you: