I came across this post from a googe search and although it is an old post, I would like to explain with more detail, for those having this same issue as you and me had.
The video and many guides fail to explain two step that are not very obvious for non experienced users:
- where to create the SSH key, where to put it and when to create it
- how to execute the Screenly installation script and how to get GIT and where to install it
Not in Raspberry Pi. With BalenaOS you cannot root into your pi console because it asks you a username and password. It is not pi and raspberry, neither your balena username and password. Basically you cannot use Raspberry Pi terminal after installing BalenaOS. It means no ways to install vnc server, vnc client, activate ssh, no access to raspi-config or edit files directly
Not in Balena terminal. If you try “sudo apt-get install wget git-core” in the terminal it wont be recognized. Because it is not the way it works. It uses special Docker packages.
What they mean with install GIT it in "your development computer " is that if you use windows as your OS, you need to download and install a GIT client like www.git-scm.com
Once installed, open it and you will have a linux-like terminal in your Windows OS.
At this point, you already should have created a Balena account (skipped the SSH step) and a GitHub account.
A newbie mistake is to think that the SSH key should be created in Raspian Lite terminal before installing BalenaOS. That wont work.
The SSH key needs to be created in the GIT program that you installed in your working computer, in this example, in the Windows GIT software.
Open the GIT terminal, and in this terminal you can execute the codes found in this guide https://help.github.com/articles/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent/
Note: the code does not need to start with the symbol $, you omit that symbol: ssh-keygen -t rsa -b 4096 -C " firstname.lastname@example.org "
After the key is created, continue working in the GIT terminal to add the SSH key to your GitHub account, use this guide: https://help.github.com/articles/adding-a-new-ssh-key-to-your-github-account/
Next step is to manually add your SSH key to your Balena account or import it from GitHub.
Now the real problem, how to install Screenly OS?
It is done in the same GIT terminal (in your Windows OS). You need to execute the installation code there.
git clone https://github.com/Screenly/screenly-ose.git
(It will get a copy of Screenly and download it in your Windows hard drive)
git remote add balena @git.balena-cloud.com:/.git
(it opens the folder where it was download it and then add balena info to it)
git push balena master
(the screenly ose image now contains your balena info and it is ready to be send to their servers)
After executing those commands, the Screenly image downloaded into your windows will be uploaded to Balena, then processed in their servers and then automatically downloaded to your Raspberry Pi device.
Once it is done. You have correctly installed Screenly OSE in Balena.
Note: Screenly updates commands will need to be executed in the same GIT terminal installed in Windows. Not directly in Raspberry Pi. Also, i haven’t found a way to install and execute cron jobs from Balena terminal