Shooting angle and power bar (2D)

Hey there.
I’m new to Unity. Currently going through the Learn page and reading tutorials.Anyways.
I’m testing stuff and want to create following:

There are 2 GUI elements above the player: A power bar and one that represents the angle you shoot at. The first click is starting the power bar animation (looping). Depending on wether you click when the bar is low or high the power of the shoot is changing. Same with the shooting angle.

My question is: With what do I achieve this? Can it be done with a simple function? Or does it take coroutines and enumerators?
You don’t have to post a code just tell me the walkthrough.

Thanks in advance!

Here are the bars (just a sketch):

alt text

alt text

First bar, you can just use Image type filled. And fill the image from left to right.

Second one, you can make small needle thing and just rotate around the bottom left corner.