The Elura does not do direct analog-to-digital conversions into the computer, as far as I know. You have to convert analog to DV tape first, then download that to the Mac.
Here's how I do it: the Elura should have come with a black cable with red, white and yellow RCA jacks on one end and a special mini-jack on the other. Plug the RCA jacks into the corresponding outputs on the analog camcorder (or a VCR), then plug the mini-jack into the Elura's analog port (below the Firewire port). Turn the Elura on "VIDEO", then press the "REC-PAUSE/LINE-IN" button inside the LCD screen compartment (it will start out in pause mode). Then play your analog tape, which will show on the Elura's LCD screen. When you want the Elura to start recording, hit the regular "PAUSE" button. You can use that PAUSE button anytime while the analog tape plays, in case you want to skip any parts of the analog tape.
When you're done taping, rewind and download the DV tape into your Mac in the usual way via Firewire.