Burning a created movie onto a DVD

I have iDVD on my older iMac & wonder if it would be possible to transfer/copy IDVD from there (& how best to do if feasible). Or reading some of the internet forums, wonder whether I would be better to consider third party DVD burning software. IDVD does not appear to be available in the App Store as far as I can see.
Any help, suggestions would be appreciated. Thanks,
David Chaplin