Need help with grid paper
 

I have a kit for water color wall hanging I seen where I can purchase grid paper to make it easier well I found the grid paper but can not figure out how to go about using it. Is it used the same as paper piecing? Any help will be appreciated

Typically the watercolor quilts are done on a grid fusible interfacing. The squares of fabric are ironed onto the grid(arrainged in a image you want) , and then the interfacing with the fabric squares is folded first either in vertically or horizontally then sewn, once all those are sewn , so the grid in the other direction. You use the lines on the grid as your fold line. You can cut squares in any size , but most use even inch( 2 inch or larger is typical) so the lines on the grid are easiest to use.
You can reposition fabric sqaures prior to sewing .. if you just heat up the area and while warm peel of the fabric sqaure.
The interfacing remains , and is not removed.
Just a note : fusible grid has the lines in yellow, non - fusible the lines are blue. You can use nonfusible ... but I use spray basting to hold the fabric in place.