You have several options how to do that:
- let someone else to do it
- draw a basic arrow by yourself (seriously, it's just 3 lines forming a shape...!)
- find some arrow you like on google and put it on your image wherever you want
- spend some time on google searching for a free software, which does exactly what you want while you don't even need to move your finger
Every graphical editor can be hard to use if you're a complete computer noob. I don't know of any ....-proof software, which can read your mind and do it for you. If you have trouble drawing 3 straight lines, try to consider the first option I mentioned in this post.