Have a Question about Activity Log!!??

Okay im 2 days new here and i'd lyke to know do you have to put down every hour/min. of activity for your whole day?? And if you dont put that your sitting for an hour or walking for 30 mins. does it count calories still being burned through out the day?

Say i missed putting something in for 2 hours out of the day...does it still some how put/show that i burned calories for that 2 hours?

Help me out on how that activity log works....lol

Thanks <3 Amanda