In this section an advertisement about the development of a game can be published. With images and videos without placing it if you are not finishing? Announce it in development mode. Or it is necessary that it is finished.
See the rules of the Release Announcements category. A project doesn't have to be finished. It's hard to define "finished" anyway. You can release a demo, preview or alpha build. But if you announce the release, then put some effort into it. Make a nice, interesting announcement. That's why the rules say to add at least one screenshot or video. If you put effort into your release announcement, people will notice, even if it's just text. But most people just write a sentence or two in a hurry.
The project to be placed. if I put it with the option in development. is it listed in the search section?. or I can put it in private and give the link in the section thread. it's just that if it's not finished. it will only contain images and a video. Description and others of the project. if it appears in the search they will think that it can be downloaded. and it's not ready yet. it's just to announce it. So, could that link be placed in the announcements section?. in private?. that it can only be seen by those who enter by link of the Announcement or by my profile.
Linking to a private project makes no sense. You can make it public without uploads, but it won't appear in searches. Some people announce their games even so. Maybe you want them to know in advance that your project will be released on a certain date. But then make a good project page and a good release announcement.