Hi arkindal,
Since game rating in the AppDB is platinum, you shouldn't need any patched Wine (even if you did, we would have taken care of compiled a patched Wine).
So, all what's needed is some installer script; PlayOnLinux installers are written as Bash shell scripts, so having some programming notions of statements, variables, conditions can help, and so does some knowledge of Bash. Things specific to PlayOnLinux are documented in
scriptwriter's documentation, well at least most of them (documentation could be updated).
You can also have a look at
existing install scripts, specially other recent Steam install scripts, if you prefer learning by example.
I'm no specialist of Steam support in PlayOnLinux, but I should be able to help you with just about anything else, if you have questions.
Regards,
Pierre.