your owner’s manual should show you where the jacking points are on your vehicle. always use jack stands too. as far as the belt change, take a picture of the routing location just in case. most vehicles will have a diagram somewhere under the hood.
How to replace the drive belt on the Nissan Sentra 2007 to 2012 - YouTube
but maybe you should leave this to the pro’s if you never even jacked your vehicle up.