That should be completely safe. (Assuming you didn't put something critical in the recycle bin. :-) )
There's also a good tutorial on using Disk Cleanup on Windows 10 over here:
http://www.tenforums.com/tutorials/3012-disk-cleanup-open-use-windows-10-a.html
It discusses some other options and advanced uses, which you might want to avoid for now, but maybe they could come in handy in the future.
Thanks!!
I did tell it to delete previous windows installation files.
Hopefully, all is well.