How Do the Endings Work?
Here's how the endings work. Just take the -er (or the -e for alle) off to find the stem. Because these are all adjectives as far as the part of speech goes, they will match the noun that they modify.
In case order (nominative, genitive, dative, accusative), here's how the different genders take endings:
Masculine: -er, -es + -s, -em, -en
Feminine: -e, -er, -er, -e
Neuter: -es, -es + -s, -em, -es
Plural: -e, -er, -en + -n, -e
Just for clarification, the notation "-es + -s" refers to the fact that, if the noun being modified does not already have an "s" on the end, an "s" is added to show the genitive case. And so "This man's job" would be translated as "Der Beruf dieses Mensches."