Is this the right place to post stories by Spanish speaking writers?

Self promotion is very unpopular here. Having the same username as your domain screams spam.

In addition set your Lemmy language to your native one so it is automatically hidden from those of us unable to read it.

I've noticed I'm getting downvotes.

This just means you're on a site that has votes. You could say in a post "the sun rises in the east" and someone will downvote it for some asinine reason or another. If the client you're using supports it, just hide the vote values. Life's much easier and happier that way.

So, a few things:

1. As mentioned by slazer2au, we don't allow self-promotion. It is also in community rules (in sidebar if using web). You can make a general post here with the info about writers, or post to other sites.
2. Select language while posting. If you set the language then only people who have selected that language will see the content. Most content is by default "undetermined", which is by default selected by everyone. If you select "Spanish" only people who have that selected in their profile will see your content.
3. Don't post too much at once. There is no hard rule about it though.
4. Even with all that, some people will still downvote your posts, if you are regularly getting more downvotes than upvotes, then it simply means the community doesn't want to see this kind of content. You can try changing how you post if that happens, or try to engage them by asking how they want it.