How do I install sv.net/classic with wine on macOS? How do I install sv.net/classic on macOS? That's a program you can use to submit information about your employee for german general social welfare insurance purposes and records. 

I don't want to buy licenses for VirtualBox and Windows. 

The ITSG support page about linux and macOS gives me a hint that I could use wine for this purpose, but it doesn't give a detailed step-by-step guide for wine newbies like me.
Download and install the current version of XQuartz (as of this writing, it is version 2.7.11).
Download and execute the "Installer for Wine staging" from the wine macOS download page.
Execute “Wine Staging” and execute the next steps in the console which opens.
Get winetricks

wget  https://raw.githubusercontent.com/Winetricks/winetricks/master/src/winetricks
chmod +x winetricks

Install cab extract, which is required by the installation of jet40 afterwards (this assumes that you already installed the packet manager brew):

brew install cabextract

Install the dependencies mentioned on the sv.net support page:

sh winetricks mdac28
sh winetricks jet40
sh winetricks vb6run
sh winetricks ie8
sh winetricks wininet

Download Setup.exe from the sv.net download page on the ITSG web site.
cd into the directory where you downloaded the installer and run the installer in wine, keeping the default settings :

 wine Setup.exe

Configure wine:

winecfg


In tab “libraries”, add ole32, oleaut32 and olepro32
Start sv.net:

 wine "C:\Program Files\svnet\svnet.exe"

In sv.net, under the “Info” menu, click the “Einstellungen” button to set up the network connection and select the “Direct” connection mode. The network test will fail, but it’s OK, the further operations will work.