If you are carrying out a thorough, comprehensive search, you should keep your search terms on different lines, and combine them together at the end. In many cases you will need to make use of the search history to see previous search lines, and use search operator to combine them together.
"social media" [textword]
social media [subject heading]
1 OR 2 OR 3 OR 4
cyberbullying [subject heading]
6 OR 7 OR 8 OR 9
5 AND 10
Here you can see that the searches for the same concept are combined with OR, and finally the two different concepts have been combined with AND (search line 11).
Build a search from the search history
Here is an example of how a structured search might look in a database.