In Illustrator click Create New or File> New
Edit the settings on the right hand side.
Change the Points drop down to Inches
Change the width to 44 inches and heigh to 15 inches
Go to File> Place
Find where you saved your image and select it. Before clicking Place check the Template box to make it a template.
The artboard is the black box on your file. Place your image inside this box by resizing or moving it. To move the template you need to UNLOCK it in the layers tab first.
Don't forget to lock it again once you're done.
On Layer 1 start drawing your shapes with the Pen tool.
Draw your line then press Enter or Esc when done to draw another line.
Holding Option to remove lines.
Selecting areas to be shapes.
Select all the paths you made with the pen tool by hiting command + A or using the black arrow to draw a selection box over them.
Select the Shape Builder tool (icon above)
Hold the Option key while the Shape Builder tool is selected to remove lines.
Once all the shapes are trimmed release the option key to select areas that you want to be shapes.
Repeat the steps above the create more shapes. Fill in the shapes with different colors to create your final piece.