Giving feedback as external reviewer for grant application outside own field of expertise
Consider asking for guidance from the grant manager(s) on this. They should have some guidance regarding the style, content, and formatting of comments. Further, as you sound as though you are a little unsure about your ability to comment on and, thus, evaluate this grant. This is something else to share with the grant manager(s) as they may decide you are not the right person to do this. Thus, best thing to do is contact whoever asked you to review the grant and have a chat about this.