I had a feeling but I still had to ask in case there was some other language out there that cares about ein/eine/einer/einen/einem/eines

Or as we like to say in English: a, a, a, an, a or a.

For the non-German studiers out there: you know how English has He vs Him ? Who vs whom? She vs her?

Germans decided to do that with their "the" (die der das den dem des), a/an (ein einer einen einem eine eines), no (kein, keiner keinen keinem keine keinez), and all their adjectives (alt, alter, alten, altem, alter... all means Old)

The good news you young grasshopper.... It kinda gets easier by the time you've done this for a year..... Kinda sorta.