powershell instructions

Author: JeremyPike

episodes/03-skimage-images.md

@@ -189,8 +189,8 @@ Images may appear the same size in jupyter,
 but you can see the size difference by comparing the scales for each.
 You can also see the differnce in file storage size on disk by
 hovering your mouse cursor over the original
-and the new file in the jupyter file browser, using `ls -l` in your shell,
-or the OS file browser if it is configured to show file sizes.
+and the new file in the jupyter file browser, using `ls -l` in your shell 
+(`dir` with Windows PowerShell), or the OS file browser if it is configured to show file sizes.
 
 :::::::::::::::  solution
 

learners/setup.md

@@ -132,4 +132,8 @@ e.g. your Desktop or a folder you have created for using in this workshop.
 
    :::::::::::::::::::::::::
 
+5. A small number of exercises will require you to run commands in a terminal. Windows users should 
+use PowerShell for this. PowerShell is probably installed by default but if not you should
+[download and install](https://apps.microsoft.com/detail/9MZ1SNWT0N5D?hl=en-eg&gl=EG) it.
+
 [figshare-data]: https://figshare.com/articles/dataset/Data_Carpentry_Image_Processing_Data_beta_/19260677