Adding the masthead
First I had to make sure to get rid of the white in the background of the masthead before putting it onto my image. This is because I downloaded a font onto Word, write the masthead, and then screen shot it.
Once I had finished making the background of my masthead transparent, I added it into my main cover image by dragging it over.
Adding a rectangle
First I added a rectangle using the rectangle tool. This made a plain coloured box (you can change the colour of it) which I could move around the image.
Then I changed the opacity of the rectangle. This allowed for you to slightly see the image through the rectangle so you don't have a really strong difference between the main image and the rectangle.