To Open a MID file in an existing SEQ file (RB and PT)
Use File - Scrap - Load Scrap.

This process simply opens the desired file and puts it on the clipboard .. then you can go to any track and click the Paste icon (or CTRL + V) and paste it from the clipboard to any location in the song.

It's a little convoluted at first, but once you grasp that that open function simply loads it to the clipboard and then you paste it wherever you want, it works a treat.

Otherwise Notation works, and I believe there is Step Record but it's been so long since I worked that way I really don't recall the route .. may be via the Event Editor, and then entering each event on the MIDI track.

I do not work here, but the benefits are still awesome
Make your sound your own!