How can I enable comments at the bottom of course pages?

I would like students to encourage discussions (i.e. comments) at the bottom of each course page, rather than as a separate section where all the discussions occur together. How can I enable comments at the bottom of each unit/page?

Also, if I enable an upload field, will other students be able to see and comment on work that has been uploaded, or is it visible only to the instructor?

Thanks.