I downloaded turbo tax home and business. I need to prepare multiple returns. I am a CPA. Should I have downloaded something else?

You are asking from TT Business, which is different from Home and Business. But neither is licensed for paid tax preparers. Please see below.

If you are a paid tax preparer then you cannot use ANY of the Turbo Tax programs ... you must use a professional program. 

https://ttlc.intuit.com/replies/3301962

Intuit (the company that makes TurboTax) has three tax software product lines for paid preparers: ProSeries, Lacerte, and Intuit Tax Online. Here are links to their web sites.

http://proseries.intuit.com
http://lacerte.intuit.com
http://accountants.intuit.com/tax/online/

For a new preparer just starting out, ProSeries Basic is probably the most suitable.

And to prepare more than five e-files, you will need to sign up with the IRS as an ERO - an Electronic Returns Originator.  How to become an Authorized E-file Provider…..
http://www.irs.gov/Tax-Professionals/e-File-Providers-&-Partners/Become-an-Authorized-e-file-Provider 

FAQ for Tax Preparer Requirements
http://www.irs.gov/Tax-Professionals/Requirements-for-Tax-Return-Preparers:-Frequently-Asked-Questions 

Do you need a PTIN (Preparer Tax Identification Number)?
http://www.irs.gov/Tax-Professionals/Frequently-Asked-Questions:-Do-I-Need-a-PTIN%3F