Damage to wall caused by chair
I only see 1 small divot but some discoloring from the rivets. I might use a tiny amount of joint compound to fill that larger spot, then use a wet sponge and pat the area with a small amount of joint compound on the sponge or wall and pat around until the texture looks good. You will need to paint to hide the line and discoloring, if you have the original color you can fade it in and not have to paint the entire wall. 
No brand of joint compound but as a new to diy I would find a pre mixed tub of standard joint compound found an any hardware or big box store I think it may come in a small tub about the size of a butter tub maybe larger but if sealed it last a long time. A standard dish sponge can be used rinsed and tossed in the dishwasher and can be used for dishes nothing hazardous in standard joint compound.