update readme

README.md

@@ -27,9 +27,9 @@ Go to the directory where the data files (`level1split`) are located.
 ```shell
 docker run -it --rm -v $PWD:/home/grisuser ghcr.io/vigeesh/sdc-grisinv
 ```
-This is pull/run the latest image from the container repo.
+This will run/pull the latest image from the container repo.
 
-Now, within the Docker shell
+Within the new shell,
 ```shell
 mpiexec -n 1 vfisv \
   --path='data/' \
@@ -40,6 +40,7 @@ mpiexec -n 1 vfisv \
   --out='output.fits'
 ```
 
+
 ### 2. Native installation
 
 #### Requirements