Always set the Configure field to "Using PPP Server". This will avoid a lot of hassles in MacPPP or FreePPP.
Your Search domain is msen.com; set your Name server addresses to 148.59.6.22 and 148.59.14.12. If you call in from Mt. Clemens, Troy, or Southfield reverse the order (148.59.14.12 first, then 148.59.6.22)
Adam Engst, in his book The Internet Starter Kit for Macintosh has this to say about Open Transport.
From here, you can to to FreePPP setup, MacPPP setup, or MacTCP configuration.
That's all there is to TCP/IP in the Macintosh world! If you have any difficulties, please call or email service@msen.com.