message: add cd command to documentation
diff: @@ -29,6 +29,7 @@ After you have cloned the Backstage repository, you should run the following
  commands once to set things up for development:
  ```bash
  +$ cd backstage # change to root directory of project
  $ yarn install # fetch dependency packages - may take a while
  $ yarn tsc # does a first run of type generation and checks
  