Clarified install steps

Readme.org

@@ -13,11 +13,22 @@ directory. The build system, =meson=, supports pulling down other projects and i
 * Initialization
 ** Toolchain
 I use [[https://www.jetify.com/docs/devbox][=devbox=]] to handle the toolchain dependencies. If you have not installed
-it, it is pretty easy at [[https://jetify.com/docs/installing_devbox][Installing Devbox]]. After that just run the following in
+it, I have found it best to first install Nix via the [[https://determinate.systems/posts/determinate-nix-installer/][Determinate Systems
-a shell from this directory:
+installer]] and then use the [[https://www.jetify.com/docs/devbox/installing_devbox/][Jetify Devbox installer]]:
+
+#+begin_src sh
+  curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | sh -s -- install
+  curl -fsSL https://get.jetify.com/devbox | bash
+#+end_src
+
+After that just run the following in a shell from this directory:
 #+begin_src sh
   devbox shell
 #+end_src
+
+On the first run it will take a few minutes to install the required packages and
+their dependencies. On subsequent runs it should be pretty fast.
+
 ** The Build System (Meson)
 Initialize build directory and pull down the sub projects via the meson "wrap"
 feature:
@@ -26,6 +37,7 @@ feature:
 #+end_src
 
 * Testing
+
 To run the tests:
 #+begin_src sh
   meson test -C build