That info is quite helpful.
First things first, since images are problematic for you I will try with text to explain what to do.
In the far upper corner of your screen is a blue dot with a magnifying glass inside.
Click on that and type in Disk Utility, a list will appear and the top hit will be Disk Utility, select that and a window will open on your screen that will have Mac HD in the left side box.
Just above that and hard against the side of that box is the root of your hard drive.
Click once on either to highlight, now there will be a bar with First Aid, Erase, Partition, RAID and Restore.
Choose First Aid, below the white box under those selections will be Repair Permissions, click that and give it time to do its job.
This is the first step, do that and let me know.