Update newbs installation procedure for MSYS2 (#8423)

docs/newbs_getting_started.md

@@ -42,9 +42,13 @@ We've tried to make QMK as easy to set up as possible. You only have to prepare
 You will need to install MSYS2, Git, and the QMK CLI.
 
 * Follow the installation instructions on the [MSYS2 homepage](http://www.msys2.org).
-* Close any open MSYS2 terminals and open a new MSYS2 MinGW 64-bit terminal.
+* Close any open MSYS2 terminals and open a new MSYS2 MinGW 64-bit terminal. NOTE: This is **not** the same as the MSYS terminal that opens when installation is completed.
 
-After opening a new MSYS2 MinGW 64-bit terminal run these commands:
+After opening a new MSYS2 MinGW 64-bit terminal, make sure `pacman` is up to date with:
+
+    pacman -Syu
+
+You may be asked to close and reopen the window. Do this and keep running the above command until it says `there is nothing to do`. Then run the following:
 
     pacman -S git python3-pip
     python3 -m pip install qmk