1. Login to your dashboard and click on Posts/Add New on the left.
The area here looks very much like the area for creating Pages.
2. Enter the heading of your post where it says Enter title here.
3. Write your post underneath either directly into the editor or you could do it first in Word and then copy and paste in here. See this post, How to set up pages for a few tips on how to use this area and how to customize your post with headings. See the same page for information on entering the WordPress SEO by Yoast section under the editor area.
4. Over on the right underneath the Publish button, you have your Categories listed. Choose one or more for this post. Your post will then automatically show up under that category.
5. You can also add a new category by using the Add New category function but be careful not to get carried away or you will end up with an unwieldy number and that will be confusing to the reader.
6. Underneath that you will see Tags. Here you will write a few words or short phrases, separated by commas. These are for when your readers are searching your site.
7. Under that is the Featured Image. Click on this and your Media Library will appear. Choose the photo you want to show up in the Related Posts under your posts and Popular Posts in the sidebar. Click on it and then on Set Featured Image in the bottom right-hand corner and it’s done.
8. Now, if you have done everything, Preview it first and if everything looks okay, click on Publish and your very first post is done.