Its as easy as one-two-three .. well almost : here is a perfect guide for you :
Installing lamp stack on suse
It covers installing Apache, PHP and MySQL . Follow the guide and I'm quite sure you'll get everything working in no time.
REMEMBER to open port for http server in Firewall.
I don't know what version you are using and in what format(cd/dvd), but that guide has been done for suse 9.1.
If you have newer version of suse its even easyer.
In suse10 differences were in mysql usergroup and mysql folder rights handling. Some of those tasks had already been done by default.
Note that phpMyAdmin might be missing from the version you are using. Fortunately the guide also covers the aspect of getting it from net if its not available.
Default path for webpages is /srv/www/htdocs/
Notice that also users have their public_html directories shared in apache default config.
By this I mean that if you put page (lets say something.html) in /home/username/public_html/something.html
it is available for everybody in address :
http://localhost/~username/something.html