Export your project to your desktop as a standalone movie file. Then drag it into a DVD authoring app (or otherwise follow the app's upload instructions). iDVD is no longer available as an authoring app but as a replacement others on this forum have recommended DVD Creator by Peng Guiping that is available at the online app store for about $14.97.
As likely your Mac does not have an internal DVD burner, you will need to purchase an external DVD burner. to plug into your Mac. You will also need some standard DVD-r discs. Then save your DVD project to your desktop as a disc image and from the disc image you can burn as many DVDs of the project as you want without going through the cumbersome rendering process each time. If you cannot create a disc image with your chosen authoring app, you can burn directly from the app but will need to re-render the project each time.
Take a look as this thread for some helpful information:
iDVD replacement software Recommednations - Apple Community
-- Rich