Moa / aoa stamping

The ICSI study material on corporate law for executive programme has following paragraph:

The articles must be printed, divided into paragraphs, numbered consecutively, stamped adequately, signed
by each subscriber to the memorandum and duly witnessed and filed along with the memorandum.

My questions are:

1) What is the meaning of stamped adequately ? Does it mean affixing stamps on the AOA

2) What should be the stamp amount? On what it depends?

3) A Similar provision does not appear in study material for MOA. Does that mean MOA need not be stamped but only AOA needs to be stamped?

Thanks.