docs: move usage guides to usage/, add quickstart and porting

docs/source/usage/faq.md

@@ -0,0 +1,39 @@
+# FAQ
+
+
+```{contents} Table of Contents
+:class: this-will-duplicate-information-and-it-is-still-useful-here
+:depth: 3
+```
+
+
+## Which devices are currently supported?
+
+Currently very few!  
+See [the `devices` repo](https://gitlab.com/kupfer/packages/pkgbuilds/-/tree/dev/device). We use the same codenames as [postmarketOS](https://wiki.postmarketos.org/wiki/Devices) (although we prefix them with the SoC)
+
+
+## How to port a new device or package?
+
+See [Porting](../porting)
+
+## How to build a specific package
+
+See also: The full [`kupferbootstrap packages build` docs](/cli/packages#kupferbootstrap-packages-build)
+
+### Example
+
+For rebuilding `kupfer-config` and `crossdirect`, defaulting to your device's architecture
+
+```sh
+kupferbootstrap packages build [--force] [--arch $target_arch] kupfer-config crossdirect
+```
+
+
+### By package path
+You can also use the a path snippet (`$repo/$pkgbase`) to the PKGBUILD folder as seen inside your pkgbuilds.git:
+
+```sh
+kupferbootstrap packages build [--force] main/kupfer-config cross/crossdirect
+```
+