Don't! If you have not downloaded a telnet program, you should do so before you log onto any ANSI BBS. The default Telnet program that comes with Windows95/98 is total crap. You will not see the menu displays correctly or in color. It will be very confusing for you. There are many wonderful shareware telnet programs available on the net.
My favorite place to get all my Internet add on stuff is at Stroud's Consummate WinSock Apps List (CWSApps).
Jump right to the CWSApps Telnet Apps page and get right into the fun.
(My personal favorite is Net Term)
After you download and install your new Telnet app, stop buy the 'Configure Telnet Apps for FesterWerks' page for setting the program to best use any ANSI BBS.