I have a in though the out door sleeve A. USA printed but I don't know if its a first pressing or not. it has the EAST in the middle of the label. but the matrix number has 6 numbers. I'm new and don't know what to do please help me.

how else can we know if they are first pressings or not?

help me please. I'm new and learning still. I have a Led Zeppelin in though the out door Sleeve "A" vinyl record . I need to know if it is first pressing, or what I actually have? matrix reads ST-SS-794345-L STRAWBERRY (PR) (SP) 0-5SM2- I have looked all over discogs.com ebay, popsike and I don't understand how to know if its a first pressing or not and what pressing it even is. Please send me some knowledge. Thanks amanda