You will need a WiFi router with port forwarding feature (most routers do these days) and if you don’t have a static IP (or if you don’t know what this is), you will need to use a free Dynamic DNS service called NoIP. Don’t worry – although we can’t offer support on individual routers, we can certainly point you in the right direction. Installation instructions on the above link.
Alternatively you can use my.openhab.org which is a service hosted externally and is not controlled by us or you but by OpenHAB itself. Go to http://[YOUR-HESTIAPI-IP]:8080/paperui and select Add-ons > MISC and install “openHAB Cloud Connector”. Once installed SSH into your HestiaPi (username: pi and password: hestia) and type:
cat /var/lib/openhab2/uuid
write the output down. Then type:
cat /var/lib/openhab2/openhabcloud/secret
write this output down too.
Then go to https://myopenhab.org and create an account using your details and the above information (UUID and secret). You can now access your HestiaPi Touch from a browser or your mobile app (enter “https://myopenhab.org” as a remote url and your myopenHAB account username and password as credentials). The above steps are also available in youtube format here too.

For OpenHAB2 (v10.x image – July 2018)
To monitor the OpenHAB logs without stopping the service run
openhab-cli showlogs

To start OpenHAB manually after stopping the service run
openhab-cli start

For older OpenHAB installations:
Stop OpenHAB first
sudo service openhab2 stop
and when it is stopped, start it manually
/usr/share/openhab2/start_debug.sh
once (if) loaded type inside the OpenHAB session
log:tail
and notice any issues.

SSH into and run
sudo shutdown -h now
Your SSH session will close. If you watch the Touch LCD it will display the termination messages of all the parts of the OS and then it will turn white. You can now remove power.
Note: This is the ideal way to turn your HestiaPi Touch off to avoid SD card corruption. Under normal circumstances we haven’t seen SD card corruption happening if you simply remove power as most operations are tweaked to happen in memory (tmpfs) and not inside your SD.

If you are very new to command line interface we would advise you taking a short online course by searching for “linux command line interface” on your favourite website.

To edit a file while you are inside SSH use the command
sudo nano /path/to/your/file
Then leave your mouse alone as it does not control you cursor anymore 🙂

Use only your keyboard and once you are done, press Ctrl+O to save and Ctrl+X to close.

As of 10.1 version, you can now connect your phone to the “HESTIAPI” network with HESTIAPI as the password. Once connected you will automatically be prompted on your phone to select your WiFi network (no hidden SSID supported yet) and enter the password. Your HestiaPi will restart to connect to your network and the HESTIAPI network will not be shown again if the details were correct.

For older versions see below:
Insert it in your non-Windows laptop and change the file
/etc/wpa_supplicant/wpa_supplicant.conf
by entering you WiFi’s SSID and password inside the “”.

If your network is using a hidden SSID uncomment this line:
#    scan_ssid=1

If you only have Windows machines, from v9.2 onwards, comes preconfigured to connect to a default network with SSID: “HESTIAPI” and password “HESTIAPI” (both without the quotes). All you need to do is create a WiFi network with these details before connecting power to your HestiaPi Touch. Once booted, HestiaPi Touch will connect to it automatically where you can SSH into it and change “HESTIAPI” to your regular WiFi network details. Make sure you enter your details correctly.

If even this is not possible user dexterp37 (thanks!) found some very good alternatives.

Edit configuration file
/etc/openhab2/services/mqtt.cfg
to enable MQTT authentication or change
mosquitto.url=tcp://localhost:1883
to external MQTT server if you already have one
mosquitto.url=tcp://[MQTT_SERVER]:1883
MQTT topics defined in
/etc/openhab2/items/default.items

hestia/local/hotwaterstate (two way IN and OUT)
hestia/local/heatingstate (two way IN and OUT)
hestia/local/humiditystate (two way IN and OUT)
hestia/local/temperature (OUT only)
hestia/local/humidity (OUT only)
hestia/local/tempsetpoint (OUT only)
Confirm by subscribing from another laptop to all (#) MQTT IDs and listen for published messages while you play with your HestiaPi:
mosquitto_sub -h [HESTIA_PI_IP] -d -t hestia/#

DHT is no longer supported since 10.x image. You can visit the Jessie instructions section for installing what DHT needs or you can simply run this script. (credit to paciotti)

Apart from making sure you connect the sensor correctly and add a resistor if needed, edit this file
/etc/openhab2/things/default.things
Comment out the BME lines 4 and 9 and uncomment the DHT lines 2 and 7.

Wait a minute for changes to take effect.

In RasPi Zero W there are a few more radical changes needed, explained here. (credit to paciotti too)

SSH into your HestiaPi Touch (credentials: pi/hestia)

Navigate to scripts dir:
cd /home/pi/scripts
and run:
sudo ./C2F.sh
or to go back to Celsius:
sudo ./F2C.sh
Enter hestia at the password prompt. Within seconds the temperature displayed on the left of the LCD will change to F values and after a few seconds (once the rules file gets processed) the setpoint value on the right will update too.

Username: pi
Password: hestia
SSH port: 22