1. sudo mousepad /etc/apt/sources.list
tambahkan repo
deb http://ftp.debian.org/debian buster-backports main contrib non-free
deb-src http://ftp.debian.org/debian buster-backports main contrib non-free
sudo apt update
2. install via terminal
apt-get -t buster-backports install "package"
3. install via synaptic
pilih package force version pilih yang backports