minor fixes to WRF.md

WRF.md

@@ -7,7 +7,8 @@ Besides this basic guide, more detailed information is available too:
 [Basic WRF usage, including compilation instructions](WRF/WRF_basic.md).  
 [Advanced WRF usage](WRF/WRF_basic.md).  
 [Data assimilation with WRF](WRF/WRF_da.md).  
-[Workflows for common WRF tasks](WRF/WRF_da.md).  
+[Workflows for common WRF tasks](WRF/WRF_da.md).
+[Configuration files on different servers](WRF/config_files).  
 
 Table of contents:
 
@@ -41,8 +42,6 @@ If someone else already compiled it on the computer you'll be working with, you
 
 * Replicate exactly their compilation and runtime environment (see the chapter on "Setting up your environment" below).
 
-For instance
-
 ### Option 2: Get the source code
 
 The WRF source code is available on [Github](https://github.com/wrf-model/WRF), and there are several ways to get it.