I am quite a beginner in learning and developing WordPress based website as my client needs a custom-made CMS magazine site which he could easily update the site on his own with his limited computer knowledge. Well then, I started with purchasing a few different themes which I could continue to extensively modify the existing layouts. I have activated one of the theme as the main one (/wp-content/themes/Theme-A) but quite struggling on these issues following:
How to apply the 2nd theme (/wp-content/themes/Theme-B) on one specific page under the main theme (as it comes with a new whole set of theme B)? I am totally lost as each theme has its own index.php and the rest of their set files. I am not sure which approach would be the best in calling the different themes: adding functions under the main theme folder in order to redirect the other themes or any better approach? (By the way, try using "page-theme" plugin, it serves the purpose but seems having lots of files conflict between the themes, not my final solution after all.)
Without developing under WordPress framework, creating a new page from scratch is not as difficult to understand as in WordPress. For example, I create about-us.php then I could see the file under the directory straightaway and then hand coding it from there. But creating a page in WordPress with the permalink enabled, I couldn't find the physical file anywhere in the directory (apology for my limited knowledge, please correct me if I am wrong). Then not sure what to do next when: (1) I want to create the whole page with my own design under the main theme (2) Tweak/add/modify an existing theme as they include and get and etc. with the other dependent files, takes a lot of time to track them down to the root file.