1) Write your text in the default size and colour which is medium and black.
2) Highlight your text by holding down your left mouse button and dragging the cursor over the written text and releasing the left button when you have highlighted all the text..
3) Click on the colour pallette which looks like little colored square in the grey menu bar above the text box. A menu will drop down. Just click on the colour you want.
4) To change the size, after you have selected the colour leave the text highlighted and in the menu bar look for the blue double A. Click on it and a size menu will drop down. Pick the size font you want. The changes must be done in the order above.