Understanding title, renew etc

Hello everyone and hope not to be a really big hussle for you guys, i know that i may sound stupid but i really don't know how the things must go through when buying a vehicle. I'm willing to buy a '69 Mustang and i need a few information regarding registration etc. i know that in california the title is renewed every year right? so what are the effects of this renewal? my actual title in hand will be provided to DMV and they will provide me another new title each year? for what is this anual title renew? is only if you want to drive/use the car? or...? If i want to buy this Mustang, will the owner show up with the original title (not build sheet) he got when he bought the car? he told me he is the first owner since 1969. please help me understanding california certificate of title, what happens when renewing the title?