Write about The political participation through social media

I have a PhD proposal in Media subject. It needs add new information which are about (300) words in the context and rationale parts depending on my supervisor comments which are inside the proposal text. Also, these two parts need to edit and rewrite. Thus, the work will be just in these two parts.
Actually, I have 4 pages PhD proposal (about 1700 words) already done and I need to add between 250-300 words as new information from academic references. This new information will add in different places in the context and rationale parts depending on my supervisor comments. Also, these two parts need to rewriting and editing after adding the new information. My level is PhD.