Use this forum's [u][url=http://www.webdeveloper.com/forum/search.php]search feature[/url][/u] to look up the dozens of threads already here about learning PHP.
Is it better to write php from scratch or use existing open source code?[/quote]
It all depends on what you need to do, what your skill level is, what your schedule is, and what your budget is.
How does phpMyadmin work?[/quote]
Quite well, thank you. (And see next answer)
How does MySql and phpMyadmin relate?[/quote]
MySQL is one of many relational database systems that can be used with PHP. phpMyAdmin is a PHP-base web application that allows you do do many database admin and general usage tasks via a web page interface. (If you opt to use PostgreSQL instead of MySQL -- as we do where I work -- there is a very similar app called, appropriately, phpPgAdmin.)
Teach me![/QUOTE]
Teach yourself: that's what most of us did. :p :o ?