Like most special-interest communities, we don't allow self-promotion and off-topic self-promotional posts (our topic is AI).
And you might be familiar with the often-quoted advice about when joining a new community, it's good to spend the initial time exploring and seeing what is acceptable and expected in that community, in order to be an accepted and valuable member of the community.
While members are going to be able to have their own store at their Profile page, where they can promote their services and products, that has not been implemented yet (soon). You can promote yourself in the About section of your Profile page.
So what I've done in the meantime is create a new area called "Member Services" where you can post promotional materials.
How you use it is you go to your Profile page, click on Blog and then on Create, and write your title, your post, add any links, add your Featured Image (green button at the bottom), and click on Publish Article.
I or a moderator will be notified and if all is OK, we'll publish the post and it will appear at the Member Services page.