EOS R and strobes

Hey all. New around here but I’m glad to be a new member to this community.

So my issue is this. I was doing a shoot with my alienbees 800. I went to take the image and the screen was pitch black. I couldn’t see a thing. I managed to get a few photos but I had no idea what my composition was or what it looked liked.

Now having used my DSLR (canon 70D and canon 5d Mark II) in the past with this same setup I have never this issue. Obviously it’s because one is a mechanical shutter and the EOS r is a digital mirror less camera with no shutter.

So my question is, how do I get the EOS r to actually let me take photos in this setup?

my settings were set to:

f4.5-5. ISO 100, and 1/200.

I hope I did a good job of explaining that. Any help would greatly be appreciated.