I don't know exactly what you are trying to do, however, the first place to look is the documentation. Net::Telnet

You mention: "But how to use this api to get data."
To me, this means: "How do I use the module to send commands and receive the output of those commands".

Begin with a reasonable prompt. For example, see this thread: Re: Net::Telnet + command prompt

For the rest... a good place to start is to read about the methods cmd(), waitfor() and print() from the documentation. There are also some good examples at the bottom of the page as well.