First verify if what you're seeing is the same as what SQL Server can see, by running this:
If all 3 of your files are here, you somehow created them there by accident.
TempDB is a 'special' system DB that gets re-generated every time you start the
SQL Server service.
Setup TempDB the way you want it, restart the server so TempDB recreates itself and run the above query again, to see if the new settings stuck.
If you want to still add a file somewhere manually you can do this:
ALTER DATABASE tempdb ADD FILE (
NAME = N'LogicalNameHere'
,FILENAME = N'D:\Whatever\tempDB2orWhatever.ndf'
,SIZE = xMB
,FILEGROWTH = xMB
If you want to keep all of your TempDB files but just move them around, get the info from
sp_helpdb and modify to include your paths/files/names as found here:
ALTER DATABASE tempdb MODIFY FILE (name = tempdev, filename = 'E:\Sqldata\tempdb.mdf');
ALTER DATABASE tempdb MODIFY FILE (name = templog, filename = 'E:\Sqldata\templog.ldf');
Note you should usually have multiple TempDB data files. If you don't, you are risking logical file contention, which is not pretty.
Check out Brent's blog for more info on SGAM and PFS contention.