I mostly followed this manual: https://www.lucifernet.com/2020/01/08/build-a-p25-dmr-cross-mode-bridge/
Install DVSwitch and P25 binaries:
mkdir -p /opt/dvswitch
wget https://github.com/DVSwitch/MMDVM_Bridge/raw/master/bin/MMDVM_Bridge.`dpkg --print-architecture` -O /opt/dvswitch/MMDVM_Bridge
wget https://github.com/DVSwitch/Analog_Bridge/raw/master/bin/Analog_Bridge.`dpkg --print-architecture` -O /opt/dvswitch/Analog_Bridge
chmod +x /opt/dvswitch/*
git clone https://github.com/nostar/DVReflectors.git
cd DVReflectors/P25Reflector
make && make install
cd
git clone https://github.com/g4klx/P25Clients.git
cd P25Clients
make && make install
Replace 1234567 and N0CALL with your DMR ID and callsign. Edit the XLX server address and P25 talkgroup number accordingly.
Run the following commands, each in its own "window" or use screen or tmux:
P25Reflector P25Reflector.ini
P25Gateway P25Gateway.ini
/opt/dvswitch/Analog_Bridge Analog_Bridge_DMR.ini
/opt/dvswitch/Analog_Bridge Analog_Bridge_P25.ini
/opt/dvswitch/MMDVM_Bridge MMDVM_Bridge.ini