On a text terminal, Emacs can display only one Emacs frame at a time. However, you can still create multiple Emacs frames, and switch between them. Switching frames on these terminals is much like switching between different window configurations.
Use C-x 5 2 to create a new frame and switch to it; use C-x 5 o to cycle through the existing frames; use C-x 5 0 to delete the current frame.
Each frame has a number to distinguish it. If your terminal can display only one frame at a time, the selected frame's number n appears near the beginning of the mode line, in the form ‘Fn’.
‘Fn’ is in fact the frame's initial name. You can give frames more meaningful names if you wish, and you can select a frame by its name. Use the command M-x set-frame-name <RET> name <RET> to specify a new name for the selected frame, and use M-x select-frame-by-name <RET> name <RET> to select a frame according to its name. The name you specify appears in the mode line when the frame is selected.