missing prefabs (dummy) (PLEASE HELP !!!)

I am learning unity .
I downloaded a project from version control ( and that app is live ) but I cannot build it locally ; its giving me missing prefabs ; tried everything that’s available in unity forums still can’t resolve.
Any help would be greatly acknowledged.
Thanks in advance .

p.s. The project is built using unity 5.4.2 and I am using 2018.4.17f1 (if that would help )

The project is probably not compatible to the current version. Updating it is probably much too advanced for you as a beginner. I would just try a newer tutorial to start.