All current models of DVD recorders should have a digital tuner built into them. (Just look for a 'Freeview' label to be sure).
When you connect the DVD recorder to your TV, your TV might automatically recognise the new incoming signal and switch to its 'AV' setting, so that you'll see the output from the DVD recorders tuner on your TV. Alternatively, you might have to press the 'AV' button on your TV's handset. (Note: Different TV manufacturer use different labels for 'AV'. Your TV handset might label the button as 'AV', 'Aux', 'Ext', 'Line in', 'In' or similar).
Once your TV set is displaying the output of the DVD recorder's tuner, you'll be able to watch Freeview channels. (That, of course, assumes that you're in a Freeview reception area, with a good enough aerial). i.e. the DVD recorder will do the same job as a Freeview 'digibox'. You'll change channels by using the DVD recorder's remote control, rather than the TV one.
You'll be able to record Freeview channels simply by programming the DVD recorder through its handset. You should note, however, that you won't be able to watch one Freeview channel while recording another. To do so would require two digital tuners (and you'll only have one). You will, though, be able to watch analogue TV (until your local transmitter is turned off) while recording Freeview.
Chris