if( boolean_expression 1)
then
   --[ Executes when the boolean expression 1 is true --]
   if(boolean_expression 2)
   then
      --[ Executes when the boolean expression 2 is true --]
   end
end

--[ local variable definition --]
a = 100;
b = 200;

--[ check the boolean condition --]
if( a == 100 )
then
   --[ if condition is true then check the following --]
   if( b == 200 )
   then
      --[ if condition is true then print the following --]
      print("Value of a is 100 and b is 200" );
   end
end
print("Exact value of a is :", a );
print("Exact value of b is :", b );

Value of a is 100 and b is 200
Exact value of a is : 100
Exact value of b is : 200