Payout amount is a lump-sum amount of money which your family/beneficiaries will receive if you pass away while your term life insurance policy is active. Most Financial experts recommends to have a payout amount equal to 10-12 times of your annual salary.
Policy period is the amount of time you decide your policy to be valid. If you buy a term life for a policy period of 5 years on 1st January 2020 then you are insured till 1st January 2025 and not after that. It is always advisable to select a longer policy period, since term life insurance cost increases with your age.