DSL is an acronym for Digital Subscriber Line, which is a type of Internet connection that can be run through a standard telephone line. The default setting of a DSL connection is on, and, as such, will not require you to insert a password to open a Web browser. If you need your password, you can find it without any technical or specialist knowledge. It will be available in several places.
Check the back of the modem, which should have a sticker printed on it. If your connection is a wireless router, the sticker will say "SSID Wireless Settings," which will be your password. You can enter this when prompted to allow internet connectivity.
Look through the pack that was sent with your router. The password will be printed on a sticker in the pack or will be on the inside of the box in which the router came. The sticker will be one with a bar code and not necessarily labeled "Password."
Contact your DSL provider, which will be able to give you your password or set up a new one for you. When doing this, you will need to have your account details ready, since these will be required.