When using the English word ‘floor’ counting ground floor as ‘first floor’ makes sense – ground level still has a floor and it is the first one, but it is still counted differently in different English-speaking countries. Other languages (at least Polish) have separate word for ‘non-ground level of the building’ so those are counted.
In Polish we have the word ‘parter’ for the ground floor (lowest non-basement level of the building) and ‘piętro’ for any level above it. So it is: (‘piwnica’ (basement), ) ‘parter’, ‘1 piętro’, ‘2 piętro’… This makes complete sense… but I still remember it being confusing when I was a kid. A ‘floor’ (the bottom of a room) is ‘podłoga’.
So, answering the question: there are three ‘podłogas’ under the second ‘piętro’ here.
Non-toxic glue would be starch or gelatine - both used as base of some ‘real glues’, both with valid culinary use, including exactly this use case. We just don’t call those ‘glue’ in this context.