files/settings needed for new frontend plugin

what files do i need to modify / add if i want to add another frontend plugin (pi) to a TYPO3 extensi开发者_C百科on? this should be done by hand and not with the kickstarter...

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The best way to learn the answer to this question, is to make another plugin like the secondary one you want to add, and then try to merge the two manually. The answer to the question is dependant on what your secondary plugin does.

[Rest of explaination removed, as it struck me that someone must have answered this before. Googling "typo3 add plugin" reveals Ingo Renner's Adding a new plugin to an existing extension on the first page. Please do a little research before asking!]