Hi,
Youtube says bullshit. There is absolutely no need to change the Apache listening port number.
> Syntax error on line 25 of C:/wamp/alias/phpmyadmin.conf: Expected </IfDefine> but saw </Directory>
You've made mistakes by modifying files.
Delete all your changes in all files.
Put in the state where it was just after the installation then return here to explain what the problem is.
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Documentation Apache -
Documentation PHP -
Documentation MySQL -
Wampserver install files & addons