Pictures?

Here's pictures

I'm the farthest thing from a plumber, but looking at your picture it looks like the plate is cut out on the right hand side, where I circled. Can it be slid to the left?

I tried moving it with a screwdriver in different dire6but stopped when it started to bend.

Delta has installation instructions on the internet.

Your faucet may use a clip.

Thanks. I found a YouTube video posted by Home Depot showing installation of a faucet similar to mine. Apparently I need to remove the hose coming out of the left side of my picture and there is a nut to be loosened above where the hose attaches. That nut looks to be what is holding that brass plate (clip) in place. I've included a link to the video provided by Home Depot for this type of Delta faucet . https://youtu.be/cgigb9ntV9E

Here's a link to another video that shows what appears to be exactly my particular faucet so I think I have this now. https://youtu.be/4GLyj7qd_o0

This faucet was destroyed by the leaking clipped sink that rust-welded the nut to the stem. Superman isn't getting that nut off, I promise. You can't try the heat trick or you'll melt the plastic supply lines. If you're not cutting a new sink cutout as I was here, the only way that faucet's coming off is with a diamond blade on a grinder.

I sure hope mine isn't that difficult.