I need Little modification in my wordpress Theme

I use detube theme , my site is adult website! I want to add a little modification in the video posting seciton - if i post splitted video i want that it will a little tab under the video that you can press on it and you will see the second part 2. i dont want it to be on diffrent posts ( i will show example of something like this in other website). Also i want to add a template for posting so when i select category he will add auotmatically few tags that i will give so i dont need to do this manual, and also to add posting template that in the body of the post it will be the Subject Bolded and line with the word Description: i want it to appear automaticaly when i try to add new post