Do I need a lawyer to adopt?

At a minimum, It would be wise to consult with an experienced immigration lawyer prior to attempting to ADOPT.
http://adoption.state.gov/about/who/eligibility.html

(Dept. of State - Read this first)

http://www.uscis.gov/portal/site/uscis/menuitem.5af9bb95919f35e66f614176543f6d1a/?vgnextoid=c6594b5bbfb73210VgnVCM100000082ca60aRCRD&vgnextchannel=2fca18a1f8b73210VgnVCM100000082ca60aRCRD
(and the USCIS link above)

Square One:
The age of the child, and fitting the U.S. Definition of ORPHAN or CHILD under U.S. Immigration Laws.
So, for example, if there are living parents of these children, and they have not had their parental rights terminated, you possibly won't be eligible to adopt them... or there are requirements of 2 years living with the child prior to the application in certain circumstances, etc. There are extensive explanations you should read first, and you may wish at least two different consultations with these facts. That is, be leery of any advise sounding too easy or promising, rather than advise requiring many steps, and a lengthy process.

The U.S. requires that all children involved in intercountry adoption from non-Convention countries meet the definition of a child or an orphan as defined in the Immigration and Nationality Act (INA) before they can be considered for United States permanent residence/citizenship. If an adopted child does not meet one of these legal definitions, the child cannot immigrate to the United States. Similarly, all children being involved in intercountry adoption from Convention countries must meet the definition of a Convention adoptee to be adopted and immigrate to the United States.