The best way to find the Hamburg list is to search on Ancestry.com. To go directly to the collection, this is the link. If you don't have an Ancestry subscription, you have to order the microfilm from the Family History Library. If anyone knows of a free source, please add that in a comment.
If you can't find your ancestor's name in the Ancestry index to the Hamburg lists, you can search them manually for the ship and then go through that ship's passenger manifest. The typical transatlantic voyage took about two weeks, so start 3-4 weeks before they arrived in North America and go forward until you find the ship.
Here's an example of the illegible chicken scratches on a typical Quebec arrival record (and this is not the worst by far):
|Family of Gerhard Siemens, Passenger Manifest of Vessels Arriving Quebec, Canada, 27 August 1874, ship Hibernian, list 63. Accessed at Library and Archives Canada www.collectionscanada.gc.ca/databases/passenger.|
|Passenger Manifest of Vessels Departing Hamburg, Germany, 7 August 1874, ship Halifax, lines 62-64, Hamburg Passenger Lists 1850-1934, Staatsarchiv Hamburg, Germany, Indirekt Band 26, Microfilm S_13127. Accessed at Ancestry.com on 23 November 2013.|