Error message installing new OS

Hi! I’m not particularly tech-savvy so any detailed help is much appreciated!

I’m in the booting phase of installing Ventura on an IMac, mid 2011. My partner recently updated the internal SSD (which I did format to ensure it’s compatible) but we ended up having to use a separate MacBook to install the new OS/build OpenCore on an external USB because he didn’t realize it would have been best to do this on the target model. That being said, I did make sure to build the OpenCore configuration for iMac12,1 to ensure it would work with my mid 2011 IMac.

Everything installed successfully on the USB and I had no problems accessing the EFI Boot when I turned my device on, but now I’m getting an error message “An error occurred while preparing the installation. Try running this application again.” I’ll attach a picture for reference — any ideas or suggestions welcome!! Thank you in advance!