docs: add screenshots and more detailed steps for mfs example (#2229)

Author: terichadbourne

browser-mfs/README.md

@@ -2,8 +2,22 @@
 
 The MFS is a file system abstraction built on top of IPFS.  It supports all the operations you would expect such as creating directories, adding files to them, renaming, coping, deleting, etc.
 
+This demo allows you to upload files from your computer and use them to explore MFS methods from within your web browser.
+
+![screenshot](screenshot_1.png)
+
+![screenshot](screenshot_2.png)
+
 ## Running the demo
 
+Fork and clone this repo.
+
+Navigate into this directory:
+
+```
+$ cd js-ipfs/examples/browser-mfs
+```
+
 In this directory:
 
 ```