Update contributing-terms.en.md

Some grammar improvement for better readability

Co-authored-by: Matti Schneider <matti@opentermsarchive.org>

content/contributing-terms.en.md

@@ -400,7 +400,7 @@ Having understood briefly how a declaration is structured in JSON format, we nee
 3. Run `npm install`. This will install all the dependencies including the Open Terms Archive engine which will allow you to test and validate your declaration.
 4. Create a JSON file with, as filename, the service ID of the service you are adding the declaration for. This JSON file should be in the `declarations` folder of the repository. To learn more about selecting the right service ID, please read the [declaring a new service](#declaring-a-new-service) section.
 5. Visit the declaration URL and use [browser developer tools](https://developer.mozilla.org/en-US/docs/Learn/Common_questions/Tools_and_setup/What_are_browser_developer_tools) to inspect the page and find the right selectors for the significant section containing the terms you want to declare.
-6. After you've properly added your selectors and structured your JSON file, you need to test and validate your JSON file to make sure it is ok. To do this, you need to run `npx ota validate --services [service name]` from the root of the repository. This will run a validation on the declaration, highlighting any changes required.
+6. After you've properly chosen your selectors and structured your JSON file, you should test and validate your JSON file. To do this, you need to run `npx ota validate --services [service name]` from the root of the repository. This will run a validation on the declaration, highlighting any changes required.
 7. If all tests are good, make a pull request to the main repository.  
 
 You can read more about the [CLI](https://docs.opentermsarchive.org/#cli) to learn more about other tests and linting you can run on your declaration