How to use TABS in LaTeX

To use tabs, you want to use the "tabbing" environment.  (This is all
described on page 62 of the latex book).  It's probably easiest to explain
this by example:

 \begin{tabbing}
 If \= it's raining \\
 \> then \= put on boots,\\
 \> \> take hat;\\
 \> or \> smile. \\
 Leave house.
 \end{tabbing}

This would produce:

 If it's raining
    then put on boots
         take hat;
    or   smile.
 Leave house.

Tab stops are set with the \= command, and \> moves to the next tab stop.
Lines are separted by the \\ command.

Here are some of the other commands that are available in this environment:

 \+   Causes left margin of subsequent lines to be indented one tab stop
      to the right, just as if a \> command were added to the beginning
      of subsequent lines.
 \-   Undoes the effect of a previous \+.
 \'   Indents text flush right against the next tab stop.

For a full description of all the commands available in this environment, see
Section C.9.1 of the LaTeX manual.