orbi rbk50 and hooking it to a backup system

All right I'm trying again and if I don't get any help that I understand I'll just blab it on Facebook or turn in my orbi for a new system that i know can connect to a backup machine. So, once again, can i connect my RBK50 to a backup device? How complicated is it?

This board seems to have forgotten or erased my previous queries. It's been a few months since I discovered to my despair that I couldn't just add a storage device. Had I known I would have gone to some other wi-fi router, but having done through the laborious and confusing process of setting these up (and they are working great for wi-fi anyway) I am reluctant to just throw away that investment. But my family and I can not live without backup.

Adding to my confusion I thought I would try to download the new firmware but I could not log into the system and when I went that website it did not recognize me. I don't think I changed by so-called password or user admin name. So I am stuck and very unhappy.

I've abandoned any pretensions I once  had to being a gearhead, so excuse this outburst of ignorance here.

Any help would be greatly appreciated

Thanks for listening,

Dennis