If you are wanting to change the color of a graphic that you are going to place on a project, do it before putting it on the project or else it may change the color of the other things on the project too.  Unless you are using layers on your project.  In that case, it doen't matter when you replace the color of the graphic.

First, make a duplicate copy of the template or graphic, and always do that when working with any template or graphic.
You duplicate by clicking on "Window / Duplicate".
Get rid of the original and work with the duplicate.

Now magnify the graphic or template so the lines are much easier to see.
Click on the color replacer tool.
RIGHT click the "Dropper" on any part of the template line.
The color of that line should now be the background color in the style box.
Now click in the foreground color of the style box and put in the color you want to make the template lines.
Now click on the color replacer tool, then the toggle tool options window to change the properties.
I always have my size at 100 or even more for templates so it will cover more area.
Click on the middle tab and make sure the tolerance is set how you want it.
I have mine at 50.
Now just run the color replacer tool over it to change the colors.
I don't magnify to do this so I can see the entire image better, but do magnify it after to see if you missed anything.

~Summer °Ü°