You'll use this same authoring interface whether you arre creating a new post of your own or commenting on someone else's post.
First, give your post a title.
Next, you need to decide what elements your post will include. Posts are composed of rows of various kinds of content. Every new post or comment includes a text row and a media row for attached files. You can delete these or add more rows.
Type or paste in your text and then use the menu of tools to format your message or to add links. If you need the box to be larger, open it up with this handle in the lower right corner.
To submit homework, you will typically need to upload one or more files. You can drag and drop files, browse to select them from your hard drive, or, from a mobile device, create a new photo or video.
Once your files are uploaded, you can drag and drop them into whatever order you like. You can also rotate images that are presented sideways or upside down, as sometimes happens with photos taken on a smartphone or tablet. Select any image to serve as your poster, or teaser image. Or, if your uploaded files are not images, you can upload a separate poster image to give a sense of what the file contains.