I am glad to hear that.
Realize that a fundamental concept of HTML/XML is the format (or syntax) of the entities. You will begin to see this consistently but;
All HTML elements MUST BE contained within angle-brackets. They are intended to confine and delineate the element.
Inside that element there can be numerous attributes. Every element SHOULD contain a matching OPEN and CLOSE tag.
Some content here, which could be more HTML tags
Some content here
Finally, some tags which do not contain data are not required to have a matching CLOSING tag. However, they ARE REQUIRED to comply with a modified format. The most familiar example is the HTML 'image' tag:
<img src="the_source_is_metadata" style="style_modifiers_is_metadat" />
<hr /> This is another example
<br /> And so is this
Note the way this is self-closing
These are the "formal" requirements. However, many browsers will properly interpret (and interpolate) poorly structured HTML. In the world of XML there is much less tolerance, though.
I hope I have not bored you with TOO MUCH DETAIL.