First, you need to make sure the DVD recorder will accept an audio only input. In most cases, a stand alone DVD recorder will not record an analog audio signal alone.
If the recorder will accept a two channel analog input and make it work, then you simply plug a RCA cable between the cassette and the DVD.
I wouldn't count on this being that simple though.
It would be far easier to transfer the tapes to a CD recorder and then play the CD through the DVD machine. DVD is backwards compatible to CD though not always to, say, a CD-R. So you may not be able to play a recordable disc in the DVD player. There's generally no way to tell until you try.
Otherwise, you can do this through a PC/Mac based system. There are several options there. You could simply put the cassette information on a flash drive or SD card if your DVD has either input as a option.
There are a few programs out there which will perform the necessary analog to digital transfer and then upconvert the signal to a usable data stream for a DVD recorder. This though probably leaves most of your existing equipment out of the picture and would possibly require some new purchases. If you decide to go this route, use a search engine for a program which does this analog to DVD swap.
Or you could use an inexpensive MP3 player which would store the music much as you would with a SD card swap. A computer is a necessary item in this process though. Store the analog cassette information in the computer as a digital file and then send the file to the player.
You will lose all individual track data though. This is going to be a consistent problem with virtually any analog to digital transfer unless you physically sit with the system while doing the operation. Unless you initiate a location point within the digital file, it will all simply be transferred as one large file without track breaks.
If all that fails, take the tapes to any number of services in your area which will do the job for you. It will cost some money but will ultimately get the job done right and without headaches.