A good place to start is the Dreamhost Wiki “Getting Started” category, with special attention given to the “Building a Website” article, which has many links to tutorials.
You shouldn’t generally need to worry about .htaccess files yet.
You would probably also benefit from other articles referred to in the “Getting Started” section, particularly the articles in the “Understanding Dreamhost” category.
When you find a term you don’t understand, search the wiki, or Google, and you will likely find lots of help.
Of course, you can always post here for a specific question - there are many here who are willing to help. Good Luck, and Welcome to Dreamhost!