filter is used when there are likely to be more than one query sets. It something like this
User.objects.filter(join_date__year=2020)
This query will give you all the users who has signed up for your server in the year of 2020. Your query is supposed to look like below;
User.objects.all().filter(join_date__year=2020)
However, your Manager class allows your query to be shorter
You can also add a condition to exclude certain data like below;
User.objects.filter(join_date__year=2020).exclude(join_date__month=5)
By using this, you are excluding all the users who have signed up in May.
There are some methods that you can find in the django official doc. In case of filtering by number, you can use count__gte=30, which is equivalent to count greater than 30, and also count__lte=30, which would be coult less than 30.
In the case of filtering by string, you can use headline__startswith="what", which is straight forward, and I believe there is also headline__endswith="what".
And you would use get when you expect to receive only one query set. For example, if you added unique=True to an email field, you would query your user like this;
User.objects.get(email='test@email.com')