I'm 95% sure you will need to release the springs, and I'm not sure if you will need new ones if the door weight is different. I assume it is this one?
https://www.kijiji.ca/v-garage-door-...6ft/1461804469
It says it is 9 feet tall, is yours? In any case you will need to at least adjust the springs, so read up on that, it is not complicated, but can be extremely dangerous so I'd make sure you are comfortable with that. The rest of it is pretty straight forward. You place the bottom panel, secure it with nails (hammered in the door frame, then bent over to hold it in place) then stack the next panel and repeat. You will need 2 people. Then you attach the hardware like rollers and hinges, which secures it all.
You could always get it all installed and have a pro do the springs, thoguh you will need them to come by and release the old ones. If they are old, you may as well just replace them at the time as well, as they aren't that expensive and do break with age.