@TSS-Graviser The arcs and the angles actually go together. An arc is a fragment of the line of a circle. In the picture below, the yellow angle inscribes the yellow arc, because you can see that the ends of the angle's segments meet the ends of the yellow arc.
Now, I've drawn another angle that also inscribes the yellow arc. This angle is equal to the first yellow angle!
Isn't that neat? This is also how we are able to prove the Power of a Point Theorem. Do you see that since the yellow angles are the same, we can form similar triangles? It's because ---- look! There are two more angles that inscribe the same arc!
The green angles inscribe the same green arc, and so they are the same as well!
Don't worry if it takes a few times of seeing these ideas before they sink in. It's natural when you are learning something unfamiliar. Remember the saying, "You have to spend 10,000 hours doing anything in order to become an expert." So don't worry if takes time, because this is part of the process of attaining real understanding!