1.) you must show proof of payment for the whole time you are claiming. eg. if you are claiming 1 year then you must provide one bank statement from 1 year ago and one from now, if you are claiming 2 years then you need to provide one bank statement from 2 years ago and so on
2.) as many years as you are claiming points for, at least 1 year to be eligible for Express Entry
3) your students must provide reference letters with contact details, I don't know if IRCC will contact them, but they might.
Do you have any qualification to coach archery? Have you won any competitions either yourself or as coach? Been in a national team? If you have medals, certificates, news paper reports etc upload them as well.
If you don't have a website, make one now. Proper domain, have a description of your business, photos of classes, photos of students, competitions etc. Add your business to Google Maps with phone number, photo etc. The more professional it looks the more likely IRCC won't check too much. If you don't have a website it's likely that it will require a review.