Hi, you need to hook up your VHS player in some way to your PC then in Magix click the red record button on the preview screen, it'll give you options, you'll have to play the VHS whilst recoding with MEP.
Do you have a USB video capture device/dongle as shown below?
If not, you need one to connect the VCR video and audio outputs to the converter which is used by Movie Edit Pro (MEP). The make/model does not have to be a Magix dongle, however if you do have to get one, I would advise against getting a cheap one, they are often poor performers, a good brand is Terratec.
Once connected and MEP can see it - you click the Record button in MEP and from the window that opens, select Analog option, shown below,
and in the dialog that opens set up the USB device in the indicated dropdown below