If you ever need to redownload, you are hopefully making a backup copy of your files and will be able to retrieve them from there. If you aren't making a backup copy, do it. Everyone needs one, everyone.
You are doing it correctly.
They won't show in your account as they are only included during the 6 month time period. They won't be available after the subscription has expired. You can renew anytime though and add 6 months to the end of the current subscription.