a- if the guides are there, you can "turn them on" with "view > grids and views"... but that should be the default
a2- if the guides are not there, it's probably a bug: can you upload the page maker file to the bug tracker (
https://bugs.scribus.net ; if you mark the ticket as private, only the developers will see it)
b. the x in the bottom *right* corner indicates overflowing text. i don't know of an automatic way (that works) to make it longer, but it's not that hard to
ba. create a frame that is long enough (shift-click while in "create text frame mode", will create a frame that fills the area inside of guide and margins)
bb. pull the lower margin to a guide or margin.
bc. there is an "adjust text frame to height" but i really don't know what it should achieve: i've tried it out and it just changes the frame height a little bit...
bd. a long time ago, i've written a script that would fix the text frame height... but is it worth to start a script for that?
https://wiki.scribus.net/canvas/Adjust_a_text_frame_to_fit_its_content