I suggest to place the tar file in the directory you would like the files to be untarred to. Then when you untar the files should be placed in that directory.
The exception is if the files were tarred with / preceding the path. Then the files will be untarred to the root directory.

You can determine where the files will be untarred by using the t option.
tar -tvf files.tar will show you the paths of where the files will be untarred.