A portable version cannot be installed per se, this is its main difference from the installer.
If you just want NetWorx to work and don't have any specific needs for using the portable version, download and run the installer instead.
If you want to use the portable version, you have to copy
networx.exe and
sqlite.dll and make sure they both are either 32-bit or 64-bit. Some archiving programs hide the folder structure shown below
networx_portable.zip
│
├───32-bit
│ networx.exe
│ sqlite.dll
│
└───64-bit
networx.exe
sqlite.dll
For Windows x64 it makes sense to use the files from the
64-bit folder.