The adoption button is a bit more vague than the rest of the groups.  If you are searching for birthparents, family, or an adoptee, begin by filling out as much information as you know in the location.  This could be where you suspect the person may be, last known locations, or the location of where the adoption took place. 

In this case it might be most useful to add multiple locations.  In the name of the group it is suggested to insert the word "Adoption."

Group name area:

 
It is also suggested to use the comments section to give more details.