The steps are as follows:
1. Create the first tier using the floating layout technique by using only one or two pieces of foam tapes.
2. Overlaps part of the second tier on the first tier by using another piece of foam tape. However, for parts of the second tier that are not overlapping the first tier, you must use two pieces of foam tape if the first tier is using only one piece of foam tape. (The formula here is to add another piece of foam tape to the pieces of foam tape that are used for the first tier)
3. The steps will repeat for the third and following tiers but you must remember that if any parts of the upper tier that are not overlapping the immediate lower tier, use the formula above to calculate how many pieces of foam tapes to use.
It might sound a bit confusing here but once you've got your hands on it, you will figure out, what I'm trying to explain here. Give it a try on your next layout!