Open PowerPoint.
Before you choose a template, go to the search bar above and type birthday.
Choose the first template.
This template is two slides, so delete the second one before proceeding.
Customize the slide to say what you want it to say. I added a shape on the left and took out the age on the right, so mine looks like this:

Use CTRL+C to copy that slide on the left toolbar. Then use CTRL+V to paste the slide as many times as you need to get enough for your whole class.
Change the names on each slide.
To save, do both of these:
FILE, SAVE and save the whole slideshow in case you need to edit later.
Also, do FILE, EXPORT and choose JPEG and save to create an image of every slide in your presentation for uploading to Canvas.
Once you have them all saved, open CHROME. Open two tabs: one for your student information system and one for Canvas.
Open your Canvas homeroom course.
Click FILES on the left. Make a new folder for your birthday announcements and upload the jpegs to it.
Click ANNOUNCEMENTS once they have all finished uploading.
Click NEW ANNOUNCEMENT, and call it "Happy Birthday!" You may want to copy this title for all the other kids.
On the right, click the IMAGES tab and choose SLIDE 1, which should be the first kid in your class. When you choose it, you should see that image fill your announcements window. There is one more step.
In your student information system, look up that kid's birthday.
Back in Canvas, click DELAY POSTING and choose the date of his/her birthday.
Click SAVE and repeat for each student in your class. The announcements will release on the correct days and times, and you will look like a superstar teacher!