PHP syntax errors in sublime text 3?

Question

PHP

I am a beginner, please do not judge strictly and please answer in the most human language.
When writing PHP code, errors are displayed in the syntax:
phpcs: error - missing file doc comment ;
htmltidy: warning- inserting missing "title" element
Downloaded all the recommended packages including tidy and phpcs, installed them via composter and added paths to the path variable Can you tell me
what other possible packages should be installed for a beginner to work in php?