Is there a way to Add devices to an existing device collection if i have a spreadsheet list with all the names?

Im not familiar with Powersheel command to do this.  Or to do a new one with the list its also fine.  Help!  Its like 200 computers and i dont want to input them all.

There's a few ways to do this. You can use powershell to do this using the Add-CMDeviceCollectionDirectMembershipRule cmdlet. you can pipe a csv in there with just the computer names.

https://technet.microsoft.com/en-us/library/jj850102%28v=sc.20%29.aspx?f=255&MSPPError=-2147217396

I think you can also do it with right click tools available at http://www.nowmicro.com/recast/ 

Try this http://blogs.msdn.com/b/rslaten/archive/2014/03/10/configuration-manager-direct-membership-collection-manager.aspx