Server configuration SQL Server 2008 I am really fresh in the DB world so firstly,sorry about my noob question.
I have a data warehouse project to perform in a group of 3 people. 
When installing SQL Server 2008 R2 Developer in my own machine, when configuring the server, I expected that I could "use the same account for all SQL Services" in order to facilitate the access for all the group's members and I received a few errors after define username and password that block the instalation process.
Should I select Authority/SYSTEM? Or in negative case how can I define a single account without errors?

Thanks,
Francisco
Best practice is to use a domain account for SQL Services, preferably a different one for SQL Server and SQL Server Agent. These accounts should not be local admins (and do not need to be), you should use a principle of least privilege. You need to set these up in advance so you can enter the account credentials during SQL Server setup.

One question, why on earth are you doing a new project (it is 2016) on an 8 year old version of SQL Server? SQL Server 2016 RTMs [releases to manufacturing] on 1.6.2016, i.e. in just over 4 weeks. I'd recommend using that.