Entry of information is easy. Just fill in the fields you can then click 'Zones' and your zone data will appear below. The minimum entry to be useful would be your age and sex. The danger is going too fast. Set your HRM upper alarm at the top end of the zone and slow down every time it goes off.
Long runs are for aerobic conditioning and endurance.
Your AT percentage increases with as you get more trained so only use the HR zone as a guide. Threshold runs are designed to be around your anaerobic threshold. Your AT percent increases with training so you should move to the upper end of the zone over time. Intervals are run quite hard. During the work period you should be in the zone and during the rest period you should recover.