Got as far as subtemplates on the 'building-a-basic-site.' Everything worked great up to that point. Created Layout subdirectory and two files in the directory as specified. Deleted HomePage.ss from the templates directory. Revised Page.ss as per the instructions. Now get errors. Any suggestions? Tips?
Ran ?flush=1 after every revision of the Page.ss and HomePage.ss files. Tried several (numerous) times to restart with the ?flush=1 switch. Shut down the browser (Firefox), restarted the browser, again ran with ?flush=1. Long pause; now it's working. Go figure. Looks like it's back to working again. Apologies for my lack of knowledge of SilverStripe. Just found it last night.