Docs: explain how to setup the apt repo without helpers (#21194)

* Docs: explain how to setup the apt repo without helpers

* Docs: re-structured apt install docs

* Update docs/sources/installation/debian.md

Co-Authored-By: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>

* Update docs/sources/installation/debian.md

Co-Authored-By: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>

* Docs: improvements based on feedback

* Docs: appending is safer if the user for some reason wants both beta and non beta

* Docs: repo -> repository

* Update docs/sources/installation/debian.md

Co-Authored-By: Arve Knudsen <arve.knudsen@gmail.com>

* Update docs/sources/installation/debian.md

Co-Authored-By: Arve Knudsen <arve.knudsen@gmail.com>

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

docs/sources/installation/debian.md

@@ -23,8 +23,6 @@ We recommend that you run all the listed commands before you download and instal
 
 You can install Grafana using our official APT repository, by downloading a `.deb` package, or by using a binary `.tar.gz` file.
 
-### Install from APT repository 
-
 On some older versions of Ubuntu and Debian you may need to install the `apt-transport-https` package which is needed to fetch packages over HTTPS.
 
 ```bash
@@ -62,6 +60,21 @@ sudo apt-get update
 sudo apt-get install grafana
 ```
 
+### Set up repository for ARM
+
+If you have problems using `add-apt-repository`, you can set up the repository without it.
+
+Add this repository for stable releases:
+
+```bash
+echo "deb https://packages.grafana.com/oss/deb stable main" | sudo tee -a /etc/apt/sources.list.d/grafana.list 
+```
+
+Add this repository if you want beta releases:
+```bash
+echo "deb https://packages.grafana.com/oss/deb beta main" | sudo tee -a /etc/apt/sources.list.d/grafana.list 
+```
+
 ### Install .deb package
 
 Go to the [Linux download page](https://grafana.com/grafana/download?platform=linux) for the latest download links.
@@ -158,4 +171,3 @@ Refer to the [Getting Started]({{< relref "../guides/getting_started/" >}}) guid
 ## Configure Grafana
 
 Refer the [Configuration]({{< relref "configuration.md" >}}) page for details on options for customizing your environment, logging, database, and so on.
-