What are the matters considered in order to establish federal structure in nepal

Where there already is a single nation (like France or Norway for two examples) there is no need for a federal system. It is only in nation-states that have a long history of local independent states (like the German principalities that had been largely independent from medieval times until the mid 19th century) or the United States if you count the 150+ years of our colonial era) that you find the need for such a system.

Explanation:

for the points

sodium i think the chemical element of atomic number 11, a soft silver-white reactive metal of the alkali metal group.