@ Virginia...part 2 here. You're welcome.
If you are staying in Hamburg with time more or less to spare, numerous day trips are logistically feasible, ie within 1.5 hours. One such trip I would recommend dep from Hamburg Hbf is going to Schwerin, a direct shot going east into Mecklenburg.
I use the advantage of Hamburg Hbf as the junction point in North Germany in whichever direction, especially going north into Schleswig-Holstein, should you be interested in seeing small cultural and historic towns, such as Husum, Eutin, etc between Hamburg and and the Danish border.. Now for that purpose, I prefer staying in Kiel.
If you want to see the main shopping district in Hamburg, it's the U-Bahn stop after Landungsbrücken from Hamburg Hbf.