I think it all depends on the project being completed. However, in my experience with carpenters, they usually start early (around 7am) and work roughly 8 hours. Just depends.
For an overview of any given occupation, I recommend reseach the Department of Labor's Occupational Outlook Handbook. It comes out annually. It is a quick, thorough synopsis of thousands of occupations. Each text answers questions such as "What is the occupation?" "How do I enter the field?" "What are the working conditions?" among others.
Sheryl T. Smikle, recommends the following next steps:
I grew up working in my father's hardware store and worked some construction jobs on the side to make money. Carpenters and people in the trades generally start early, by 7:00 if they are on a job site. There are lots of handymen around who find their own jobs with individual homeowners or businesses. That might be a good place to start. If you can work with or shadow someone like that, you can learn and experience how to build and repair things. Learning how to do that will serve you well for a lifetime. I do almost all of my own repairs and building projects because I know how and has saved me thousands and thousands of dollars over my lifetime. Resources you can check to find someone like that are craigslist, angie's list and check with your local Home Depot, Ace Hardware, or Loews store.