My first problem is that I have a Mac. So, I needed to install a Windows 10 Virtual Machine, and installed the software which I have downloaded from Hantek web page.
The first software you have to install and configure is "Keysight Connection Expert". It's included on the software pack from Hantek. Using the USB connection, it is easy to use. You can see the instrument immediately after running the software. After that, you can send commands SCPI commands, start IO monitor and, after that, you can run Hantek HDM3000 app, which is a "remote control" of the instrument, where you can press virtual buttons, and see the readings at your computer.
For LAN connection, first you have to connect your multimeter at the same network where is your computer, and configure Network Options at Utility / IO Menu. Insert a compatible static IP address, or use DHCP. Then, after you get the IP Address at instrument, you go to Keysight Connection Expert at your computer, then "Manual Configuration", and set the same IP Address. At "Set Protocol" section, select "Socket". You must use the default port 5025, and press "Accept". After some seconds, you should see the Instrument as you have connected using USB cable.
I look forward you get it running, but if you need, just call me here, and I can try to help more.