: Try to define what you're looking for as precisely as possible. If it's educational content, specify the subject. If it's entertainment, specify the genre or type.
Putting it together, the sentence roughly translates to: : Try to define what you're looking for
In more natural, colloquial English it could be understood as: specify the subject. If it's entertainment
Given the context, the text seems to be quite informal and possibly explicit. It's hard to provide a precise translation or interpretation without more context, but it appears to mention a memory of a girl and possibly some form of adult or restricted content. : Try to define what you're looking for