[SOLVED] Template 9: modify html page into php page on the right handside

On the left handside menu, there are buttons that call htm pages to be displayed on the right handside. I would like to convert the htm pages into php pages, so that php pages allow programming to be included and executed.

However, after inserting php codes into the right side page, renaming the file name from _home.htm to _home.php, and one setting in the main.js files, the right side page is not functioning.

Could anyone please teach me the complete modifying guide, so that the right side pages can display non-static (i.e. php content) info ? Thanks a lot.