Unfold the underlay with the words “this side up” facing up. Push the layer as closely as possible against the wall and press firmly. Make sure that you lay the underlay in the same direction as you will be laying your vinyl floor. Use one of the boxes to keep the underlay in place while you are unfolding it.
Attach the second row to the first using adhesive tape. This will ensure that everything stays in place and will prevent any damage from walking.