somthing on the lines of
attach content db to SharePoint Server 2010
Its a bit of a pain to go through thro! So i would save backups of the origional content db. The migration that i did was from 2003 to 2010 tho but you can start it off from 2007 to 2010! At a glance what I saw from the url you provided is correct!
the principle is to:
1) check 2007 db is ok by using tools to check that its ready for migration.
2) copy the db to move over
3) add the db to the new 2010 sql
3.1) run tools to upgrade and check content db is all good!
4) create the new web app on 2010
4.1) detach the 2010 db
5) attach the 2007 db to the 2010 db (this is the actual upgraiding part)
6) run tools to make sure nothing is wrong, check the output files to make sure all is good!
7) you need to make some ammedments to the parent site to make sure it goes to the home page
if you had
and you upgraded the conetent databse to 2010 but now its called:
within the content databse its still called test event tho your webapp is called mysite lol but all the subsites are still there tho!
so what i mean is http//mysite.app.com will throw a 404 or 501! but if you have a subsite /hello then it still exists eg http//mysite.app.com/hello. Its just the parent site (site collection) that doesnt exists! so try to keep it the same if you dont want the hassle ;)