1 - type your text (on a different layer)
2 - click the rectangle select tool
3 - take the magic wand tool.
4 - click on "selection mode"
5 - press the square, a drop down menu should appear
6 - press "intersect"
7 - click on the text
8 - in the colours panel while your text is selected, right click on the colour you want. this will set a secondary colour.
9 - left click on another colour, this will set a primary colour.
10 - select the gradient tool
11 - drag the mouse to set your gradient
your image is also broken. once you fix it i can help you.