README: Almost complete instructions, aspirations

Will add the bootloader stuffs once it's ready!

README.md

@@ -1,5 +1,5 @@
 # Alpstrap
-These are my scripts for brining up an Alpine system!
+These are my scripts for bringing up an Alpine system!
 
 ## DEPENDENCIES
 - A sane shell like GNU Bash
@@ -14,5 +14,61 @@ You may need to install some Lua dependencies for building `apk`.  If you feel
 you've already installed them and it's still failing, double-check the Lua
 version that `apk`'s build requires!
 
+## USING
+
+### TL;DR, where's the cheat sheet?
+Set your `PLATFORM`, `ARCH`, and `BLKDEV` to bootstrap to:
+```bash
+export PLATFORM=raspi ARCH=aarch64 BLKDEV=/dev/sdb
+```
+
+> <h3>Note</h3>
+>
+> I like to use the `lsblk` command when locating a `BLKDEV`.
+
+If your system has `doas` instead of `sudo`, be sure to also `export`
+an appropriate `DOSU` environment variable for `make` to use:
+```bash
+export DOSU=doas
+```
+
+Format your `BLKDEV`:
+```bash
+make format
+```
+
+Then, install to the `BLKDEV` of your choosing:
+```bash
+make install
+```
+
+### Bootstrapping the base Alpine system
+The Alpstrap system first bootstraps the base Alpine system to a `DESTROOT`
+directory (an automatically-created `destroot` directory in this repository's
+root) for maximum speed.
+
+The system supports bootstrapping to
+[any architecture supported by Alpine](https://dl-cdn.alpinelinux.org/alpine/latest-stable/main/)
+and will support *even more* in the future once rebuilding the Alpine ports tree
+is automated!  All you have to do is specify your desired `PLATFORM` and `ARCH`
+on the GNU `make` command line as environment variables.  The currently
+supported `PLATFORM`s are `uefi` (default) and `raspi`.
+
+If you want only to bootstrap, there's a `make` target for that:
+```bash
+make bootstrap
+```
+
+## TODO
+-[ ] Add bootloader installation on UEFI (starting with GRUB)
+-[ ] Automate cross-compiling ports tree on non-Alpine hosts with only Git
+     submodules.
+-[ ] Add Bcachefs support
+-[ ] Make self-hosted installer
+-[ ] Add PXE-netbooted installer and ad-hoc TFTP server
+-[ ] Finish raspi `/boot` partition.
+-[ ] Share helper scripts with upstream Alpine??
+
 ## SEE ALSO
 * Alpine's [wiki page on bootstrapping](https://wiki.alpinelinux.org/wiki/Bootstrapping_Alpine_Linux)
+* Alpine's [wiki page on bootloaders](https://wiki.alpinelinux.org/wiki/Bootloaders)