Making personal dvd from seperate a/v sources

i am new to all of this and appreciate any guidance to help me figure this out.

i would like to know what my options are (software, file types, etc?) to make my own dvd with video and audio from 2 different sources. basically i have just purchased a car stereo dvd player and i would like to take video from a dvd or maybe a downloaded file like divx, quicktime, etc and then put in my own soundtrack. the purpose to have cool pics or video going on my moniter but listening to my own selected mp3’s rather than they sound from the original video or pic.

i realize that this is probably not as easy as a simple answer but i am looking to just start to learn and understand this and dont know where to start. i have most video and editing software but i dont know what does what when it comes to video. i have plenty of expierence in audio editing etc but am lost when it comes to video.

thanks for any help and i look to learn so that may help others here as well.