Apart from commenting on posts, which anyone can do, it’s simple if you’re a Subscriber. You can log in to change your profile. End of story.
The core members of the Group, though, can do much more and are confronted by a humongous WordPress dashboard after logging in.
The most important bit is the left-hand side and you can safely ignore the rest. From top to bottom you’ll only need the Posts, Pages, Profile and Email sections.
Posts and Pages allow you to add new and edit existing posts and pages. Posts are what appear in the blog; pages appear in the Visit menu. Feel free to post like crazy. You should only need to change your own pages and subpages, and not often.
If you’re confident enough to be uploading JPG or other image files, please keep them under 200Kb. This is the size of a decent enough photo image for a web page. If you’re uploading text JPGs, GIF or PNG may be a better format but your webmaster can translate for you.
The Profile is pretty much self-explanatory.
You can Email any number of users without having to know their addresses. The more useful aspect of this is the ability to email a group, as in Administrators, Editors, Authors, Contributors and Subscribers. These are WordPress categories of user.
The core members are all Administrators and Editors so you could send them an upload of your week’s submission as a media file. You may also want to include Authors in this.
Which brings me to what they can do. They can post but not page. They can email one or more users but not as a group.
Contributors can post and an Editor needs to approve the post. Otherwise they are only one step up from Subscribers.
This is a Page – in fact a subpage of the How To page – to give you an idea of how that works.
So, go forth and… post, page, email, whatever.