I went to page 226 of the 2019 manual here and could not find where it mentions the tilde key (~) for rests. On page 225 it does talk about what having a ~ means when it is shown in front of a RealTrack name in the Mixer. https://nn.pgmusic.com/pgfiles/support/misc/manual/bandinabox_win_2019_manual.pdf

You can enter in a rest by typing any chord name and then type a period after it: "C."


Best,
Chantelle