Readme: Add frequently asked questions

README.md

@@ -16,6 +16,9 @@ Automatically toggle your desktop’s color scheme between light and dark, switc
 - [Graphical installation](#graphical-installation)
 - [Command line installation](#command-line-installation)
 - [Contributing](#contributing)
+- [Frequently asked questions](#frequently-asked-questions)
+	- [Something doesn't work on Ubuntu](#something-doesnt-work-on-ubuntu)
+	- [Switching happens too early/too late](#switching-happens-too-earlytoo-late)
 
 ---
 
@@ -57,3 +60,26 @@ gnome-extensions enable nightthemeswitcher@romainvigier.fr
 ## Contributing
 
 You're welcome to contribute to the code or the translations! See [CONTRIBUTING.md](./CONTRIBUTING.md).
+
+## Frequently asked questions
+
+### Something doesn't work on Ubuntu
+
+Unfortunately, Ubuntu ships heavily modified GNOME components to implement some features like accent colors. Because they did so in a very hacky way instead of working with upstream and other desktop projects on a proper solution, it results in a broken out of the box experience with the extension, which expects a standard environment. Not much can be done as I don't want to code workarounds on top of hacks.
+
+To mitigate that, please:
+
+- Enable GTK theme switching in the extension preferences and choose the themes with your desired accent color
+- Enable Shell theme switching in the extension preferences and choose the themes with your desired accent color
+
+You'll have to do that again whenever you want to change your accent color.
+
+If after following these steps, something still isn't working, please open a new issue.
+
+### Switching happens too early/too late
+
+There's a hidden setting to configure the offset (in hours) applied to the calculated sunrise and sunset times, you can change it with the `gsettings` command:
+
+```
+gsettings --schemadir ~/.local/share/gnome-shell/extensions/nightthemeswitcher@romainvigier.fr/schemas/ set org.gnome.shell.extensions.nightthemeswitcher.time offset $DESIRED_OFFSET
+```