Now you are running Metasequoia without an authentication 
of a serial ID. You can use basic functions provided in the 
"Beginner mode". However, more advanced features for the 
modeling, exporting to various file formats except MQO 
(an original file format for Metasequoia), plug-ins, 
scripts and so on are not available.

You can remove these restrictions by purchasing a license 
for the Standard edition or the EX edition. 
And you can get a trial license for the Standard edition 
or the EX edition and try it before purchasing a license.
Please confirm details in the Metasequoia official web site.