When you subscribe to a channel, you'll see new videos in your Subscriptions feed. The Home feed may also show videos from your subscriptions, along with recommendations for channels or videos you may be interested in.
If you unsubscribe and then re-subscribe to a channel, your notification settings will be reset to personalized or no notifications. If you'd like to get a notification for every upload, make sure to turn on all notifications.
To get to your Subscriptions and What to Watch, follow these instructions: