Just to add to what Greg said... you don't really want to use the tab at all
in this case. You want to use the Hanging indent setting to handle
everything for you. That way, you don't need to insert a tab at all.
The behavior you're seeing--pressing Tab indenting the entire paragraph
rather than inserting a tab character--comes from the setting "Set left- and
first-indent with tabs and backspaces" (Format - AutoFormat - Options
button - AutoFormat as You Type tab - in the Automatically as you type
section.