Nice work here Martha.
Remember to use the formal APA style organization for Method sections. It should be it’s own section entitled “Method”, centered and bolded. Within should be the subsections on Participants, Measures (or Materials) and Procedure.
What you have written in the first paragraph under “Research Methodology” should be divvied up amongst those three subsections.
Within your Participants section should go the details about who you’ll study and how you’ll recruit them. If you’re recruiting families, indicate what their inclusion and exclusion criteria might be. If you’re recruiting from schools, indicate how you’d be doing so. Also include an estimate of how many participants you hope to recruit, and any demographic variables you’d plan to record.
Under the Measures section you should include the details of the materials you need to measure your variables. You mentioned a Behavior Frequency Scale – is that a published instrument? If so, make sure to cite it and clearly identify the ways it will measure your variable of interest (and remember, violence is just one kind of aggression). If it’s an original scale, keep in mind that you’d need to spell it out in it’s entirety as an appendix.
How will the scale be administered? Is this all done online? Face-to-face? You also mention an interview – is that how you’d gather data? Be specific here, and include it in your Procedure section.
Also, note that your references aren’t fully in APA style. The Coyne reference needs to be disentangled from the Cuellar reference, and the Cuellar reference needs to clarify the nature of that publication (book? journal? other?). Both Coyne and Lochman references are titled “Aggression in children” with no other information.