Wow, where to begin?

Have you ever designed a database before?

Did you get to help with putting together the business requirements?

Can you talk to the people who put together the business requirements?

Can you talk to the end users?

Have you ever used a product like Visio or Erwin?

What version of SQL Server will you be using? Is it the same version as the current database?

Is there an interface you have to connect to? More than one? Will they also be redesigned?

What sources do you have for the data? How frequently does it come in?

Can you do whatever you need to redesign this database or are there restrictions, things you can't change?

What's your time table? How long do you have to get this done?

Redesigning a database can be a lot of work. You have to understand the current database and what the new one needs to be. You have to be able to not only diagram this new database, but understand and map how all the old data will fit and what new data there will be.

If you have the time, when you're doing this, you should analyze the existing data and the estimates for the new data and make sure all the data types are the best fit they can be and if there's a place for calculated columns, sparse columns and other enhancements, depending on the version of SQL Server you're using.