Mini Monitor picture all scrambled

Hi, I'm new and a tech nobody,
I work on the latest imac, os 10.15.6. 3.6ghz 10 core i9, 128gb, amd radeon pro 5700xt 16gb.
I edit in Premiere. I bought an ultrastudio mini monitor for my playback on a hd tv. I don't know how to set it up. When I turn on Blackmagic in Premiere, the picture on my tv is just scrambled like crazy.
Can anyone guide me to a solution?

Thanks a lot in advance.

Did you install the Desktop Video software first?
Does it happen too if you try the free version of Resolve?

Thank you for the reply.

I don't think I installed the software first. I think I connected the mini monitor first and then I searched for the software. I didn't know I needed software for this. Schould I restart? Uninstall the software, remove the monitor and start over?
I havent tried resolve yes. I dont have any experience with resolve. I'll try this as well.

Thank you.

It is possible your TV can't display the frame rate setup you are using. Some some other project rates.

Did you install the Desktop Video software first?
Does it happen too if you try the free version of Resolve?

Thank, I got it to work. I uninstalled the software, removed the mini monitor and re installed the software.
At first it didn't make a difference but then I started playing around in the settings and turns out I need 1080i50 instead of 1080p25.

So thanks a lot, never could've imagined it would be this simple.

Regards