Press v and then arrow keys (or h,j,k,l,w,$) to highlight lines of text.
Type > or < to indent right or left.
(to indent more, type 2> or 3>)
(to change your indenting/tabbing to use spaces and not tabs, type :set et)
(to set auto-indenting, type :set ai)
(to set the tab-size, type :set ts=2 (or whatever number you want)
(also, for tabbing-size, set shiftwidth (>) by typing :set sw=2)