Update README.md with an extra step

I don't know if this absence is because is too obvious, but I couldn't leave it behind. I hope you can fix it proper English phrasing, as English is not my mother language.

1 files changed, 5 insertions, 0 deletions

diff --git a/README.md b/README.md
index bea307f..e832203 100644
--- a/README.md
+++ b/README.md
@@ -76,6 +76,11 @@ If you want to do this from any branch in this repository, follow the manual ins
 ```bash
 mkdir themes; cd themes;
 ```
+2. Start Git on this folder: 
+
+```bash
+git init
+```
 
 3. Now simply add a Git submodule pointing to this repository, like so: