So, if you want to write your posts in HTML, this is the right place to come and learn. You have to learn to write a heading, a paragraph, insert a picture or a link, style your text and write lists. Here are the codes for all of the above.
A Heading - <h1></h1> is the biggest you can go in headings and you and go all the way down to <h6>A
Paragraph - <p></p> You insert your text in between those two tags.
A Picture - <img src="pic_mountain.jpg" alt="Mountain View" style="width:304px; height:228px";> You will put your image source and then the pictures width and height.
A link - <a href="url">link text</a>