As you gain more reputation on Project Management SE, you will gain more privilegesprivileges that will help you contribute more to the community moderation of the site.
The most basic way to help in these situations is to flag the question as spam. Anyone with at least 15 reputation can flag a post.
The moderators on the site will then respond by either leaving a comment on the question/answer, improving it by editing it, closing the question, migrating the question to a more appropriate site, or in the most extreme cases, deleting the question/answer.
As a 1k user, you can flag questions and answers, and you can vote to close a question. It takes five 500+ reputation users to close a question.
You also can edit questions and answers without approval, and you of course can leave comments to help guide users who could improve their questions. I've seen you leave comments on questions that ask the original poster to expand or clarify, and these actions serve as a great signpost to new users and to help make the community more aware about what the Q&A format is about.
In regards to the users who have been spamming the site, if it continues, we do have ways of dealing with this behavior.