On your website's dashboard's sidebar, hover on the "Projects" option and you will get a few options. In that select "Add Project". You can do the same from the "New" option in the top bar.

In the next page fill up the Project title and add an excerpt, then in the post content are type "/gallery" which will show the gallery block, select it.

Now select the image from the Media Library or upload new images and then Publish/Update the project.

That's it you have now added a new beautiful project successfully.