Your membership will begin the day you purchase it and lasts for the badminton season it is purchased in, normally from the 1st August of one year until the 31st July the following year.
For example: The 2023/2024 badminton season begins on 1st August 2023 & ends on 31st July 2024. Your membership should automatically renew (unless purchased for you by your club secretary) for the next season once the current one expires, however, should you choose to cancel/halt a membership subscription, you would need to manually renew your membership for the new season.