What in the world is a .el8 file?
The data vim showed you when you opened the binary file contained the string eLecta, which points me to eLecta, a virtual classroom software.
Since the software is commercial, your teacher should have supplied you with a player embedded in some web-site rather than a standalone download. It uses Java to play the file.
Otherwise you can maybe try installing the free trial to play the file by setting up your own course.
El8 can be played online only. Please ask your teacher to give you a playable link instead of a file.