Since this main page is still set-up as a blog, with new posts going to the top of the page, you either want to set you home page as a no comment page that only displays your welcome message or have a separate welcome message page.  For this sample, I've set up a separate Welcome Page and will leave this one as a blog set-up for new posts on class happenings, projects, assignments, etc.

If you have specific information going out during the week, you can write your posts ahead of time and schedule their publication date.  Make sure you check your time zone.

You can also add labels, which are like tags or keywords, so people can search your blog based on these labels.  For example, if I have a newsletter type post each month, I could add the label 'newsletter.'  Parents and students could search your blog for newsletter and it will show all the posts with this label.

Don't forget to spruce up your post with an image.  You could even get your students to take the pic of the day or week.  Just remember to be cautious of student names getting into the photo.