Hello Elliot,

I'm a newbie too but I change font sizes as follows.

{\tfa Big text}
{\tfa\bf Big and bold}
...

Font size selectors from the smallest to the biggest are
\tfxx \tfx \tfa \tfb \tfc \tfd

You told about a manual, but there are a lot  of manuals around. 
-- 
With best regards
 Vyatcheslav                          mailto:yatskovsky@gmail.com