I just checked and I'm not seeing any .sea files for the download... it's all zips.

Download the second zip, IM0004783-01_Victoria42Base.zip

Unzip the file.

Extract the contents folder

Remove the Runtime folder from the Contents folder

Merge the V4 Runtime folder with your destination Runtime

Navigate to the installed Libraries folder in the Runtime

 Find the !DAZ folder

Double click the DzCreateExPFiles-V4.bat file. The script will do its thing, this will prep the morph channels for V4 cr2.

Load V4. Apply any additional morph packs.

You'll probably want to fix her shaders first thing...