how to adjust valves in SPI SOHC engine in ford focus

Hi,
I wonder how to adjust the valves in my SPI SOHC 2002 Ford Focus?
engine doesn't run smooth it rocks a little bit and my friend told my that
i should adjust valves.
He said that especially valves on the 1st cyl are working wrong

by the way what are the settings for gaps for intake and what are for exhaust valves?
should I do this when engine is hot or cold?
all the best
Arek

if u got any info pls email me: areksnopek@gmail.com

This contains some good information.
http://www.focusfanatics.com/forum/showthread.php?t=117788