The instruction is in the Czech and is for the decasl. It is a kind of a warning with the info on how to apply them. However the decal sheets aren't complete. There is the lack of one of the white discs for the red Hinomaru markings. Also I can't see any numbers and unit markings that were used for the plane for sure.
The "mosaz" word in the Czech language means brass in the English. It looks like the "0,16" is the thickness of the plate and the "4x" may to be the number of everything. The "KAREL" looks like the name of the manufacturer.
BTW what is the upgrade set number?