Difficuilty in developing new themes

Hi, I am new to wordpress themes development.
I have stuck up in thing things like
My page has few custom fields like title, description, upload audio file, upload an image etc etc, And I want whenever I select any of the audio or image file, so that content should get added into my post so, that it will be display very easily onto the front end.
I am facing problem for putting the value of audio or image file into my post.
Any help will be appreciated.