I am using Ubuntu 18.04 and installed openhab 2 (manual installation) succesfully. I wanted to implement openHab DM (https://github.com/uni-tue-kn/openhab-dm). I thought to replace the openhab-core, openhab-distro and smarthome folder but i cant find this folders in my system.
i downloaded openhab.zip folder and there i have the folders: addons, conf, runtime, userdata.
Somebody has installed openhab-dm successfully and can explain which steps to do?
opt folder is empty. If i search in the filesystem i get no results for openhab-core or openhab-distro. How is this possible? But openhab works.
If you did manually install your openHAB according to the official docs this command determines where the files are located:
sudo unzip openhab-download.zip -d /opt/openhab2
So the files should be in the folder /opt/openhab2 or whatever folder you have chosen during installation 
oh ok thanks. yes i have installed it in home directory. But in the openhab2 folder i cant find openhab-core, openhab-distro and smarthome folder.
Quite easy, they don‘t exist, as those are just repository names.