First, register.
You are allowed to put the publication on other site (that is your own site where you can add ads to earn) and put on this site a link.
You can publish in this journal anything scientific. You are only required to follow scientific or mathematical (or a “scientific philosophy”) method and Google guidelines (you should know them: no plagiarism, no call for terracts, etc.)
It is OK to have lyrical digressions and other non-scientific fragments (personal opinions, theology, etc.), unless they are highly irrelevant or too long.
When publishing you must check in the sidebar the category Scientific publication, you can even publish a draft; after your article becomes mature scientific article edit it, turn on Considered ready category checkbox and save again.
There is no rule disallowing re-publishing already published materials.
You must appropriately refer to sources, but self-references are not strictly required. When referring to sources you must follow interests of the authors.
Don’t forget to add many relevant tags.
Other users will review and moderate your article.
By publishing you do not transfer the copyright, but give us irrevocable non-exclusive right to distribute your work on any media.