not 100% understand what are the html tags are
In the simplest terms, HTML “tags” are a way to define the type of information you want to display on your web page. They’re also used to structure content.
There are a range of tags you can use but here are some simple ones, notice how each tag is opened and then closed.
<h1> You can use the h1 tag for a level one header. </h1> <p> You can use the p tag for paragraph text. </p>
You could also think of tags as containers when using them to structure your page contents. The <body> ... </body> tags for example contain the body of your website.
I hope that helps you understand what HTML tags are and how they’re used.