How do i save & open sessions in N-track 9

save & open sessions in N-track 9

im new to mobile phone recording , i got ntrack9 for my note9 phone after using audio evolution which feels cumbersome at times, ntrack feels simpler and more intuitive,
my main issue since i got it last week is "closing saving and opening sessions,
i still dont know how to “CLOSE A SESSION”
so if i want to go to another session i often just use the “OPEN SONG” option
but when i go to the window to "select " the song it asks me if i want to “DELETE CHECKED FILES” ?

i just want to be able to start a song, record, SAVE and CLOSE THe SESSION and to be able to “OPENb A SONG” form sessionlist
any help will b appreciated. thanks guys