how to get repeats at various bars?

say i have 16 bars, and i want bars 1-8 bars to repeat 'n' times, bars 9-16 to repats 'n' times.

opening "edit repeats and endings" dialogwhen i try to set the repeats if i don't check 'generate new bars' the OK-make repeat is greyed. with a message, error: chorus length is too short. ending needs to advance to 47. warning; the chords in the repeated regions do not match.

then when i do check "generate the new bars" it adds a bunch of bars which i don't want.

i'm playing it through the practice window, practicing chord changes at various tempo's so not really creating a song, want to insert repeats at various bars.

how to do?