The Generate Scripts wizard is unavailable because you are using a very old version of Management Studio Express. The 2012 version will work just fine against 2005 instances, but there is no longer an Express edition anyway, because all of the SSMS features are now available without any license.
Download the latest versions here:
https://docs.microsoft.com/en-us/sql/ssms/download-sql-server-management-studio-ssms
I list downloads for the older versions at the bottom of this post:
https://blogs.sentryone.com/team-posts/latest-builds-management-studio/