Starts with data structures refs #114

Author: JJ

doc/Language/structures.pod6

@@ -6,8 +6,15 @@
 
 =head1 Scalar structures
 
-TBD
-=head1 Structures with an internal structure
+Some classes do not have any I<internal> structure, and to access parts of them specific methods have to be used. Numbers, strings, and some other monolithic classes are included in that class. They use the C<$> sigil, although complex data structures can also use it.
+
+    my $just-a-number = 7;
+    my $just-a-string = "8";
+
+There is a L<Scalar> class, which is used internally to assign a default value to variables declared with the C<$> sigil.
+
+
+=head1 Complex data structures
 
 TBD