The safe way to view an eclipse is to use a pinhole projector box as demonstrated in the following video.
You can find detailed instructions for making a pinhole projector box on this website: https://www.timeanddate.com/eclipse/box-pinhole-projector.html
Below is a youtube videos that gives you instructions.
1. I would tape up holes in the box that let light come in and shine on the end of the box where you the screen has been taped. This is the web link for the video.
2. The longer the distance between the screen and the pinhole, the better will be
the visibility of the projected sun. Thus, if you are actually using a box, a tall box, works best.
3. Remember to remind students that the earth is rotating, which causes the Sun to apparently move toward the western horizon.
Use the following website to find out when the eclipse starts and stops where you live. You will also discover a video showing how the moon’s shadow moves across the sun where you live.
4. The moon’s shadow basically moves from west to east across the sun as the sun apparently moves toward the east. The sun’s apparent movement is due to the rotation of the earth. The moon is actually revolving around the Earth in a counterclockwise direction as viewed from the north pole. Thus, the moon moves toward the eastern sky about 13.2 degrees every 24 hours. At night, in comparison to stars, the move can be seen moving about 1/2 degree every hour. It appears that the stars are passing the moon as they move toward the western horizon.