Update upgrade instructions to run yarn install, re #9841

releases/7.4.1.md

@@ -67,10 +67,14 @@ Python:
             "arches-dev-dependencies": "archesproject/arches-dev-dependencies#stable/7.4.1"
         }
     ```
+    In your terminal navigate to the directory with your project's package.json file. Then run:
+
+        yarn install
+
 
 4. Start your application server in a separate terminal if it's not already running. Your webpack build will not complete without your application server running.
 
-5. In the same terminal window where you ran `yarn` ( on the same level as `package.json` ), run `yarn start` or `yarn build_development`. This will generate your `media/build` directory.
+5. In the same terminal window where you ran `yarn install` ( on the same level as `package.json` ), run `yarn start` or `yarn build_development`. This will generate your `media/build` directory.
    - If running your project in development:
      -  `yarn start` will build the frontend of the application and then start a webpack development server
       - `yarn build_development` will build a development bundle for the frontend assests of the application -- this should complete in less than 2 minutes