ASM Question

I'm very sorry if this is the wrong place and I'm very sorry if this is the dumbest question you've ever read, but I would love a small bit of clarification. I've spent the last 14 and a half hours familiarizing myself with the hexidecimal system, binary system, ASM terminology (I know and understand LDA, JMP, STA, NOP = EA, etc.), and I've learned a ton. My question is how do I take and apply code based on assembly? Do I literally create lines of code, say in Notepad ++, save the file as a .asm and patch it to the rom with an assembler (such as asar)?

For instance, if I wanted to change the sprite ID of the moogle suit, do I copy and paste the following into Notepad ++, have it be .asm, and patch it with an assembler?:
C2/2872: A5 C9
C2/2874: C9 9F 
C2/2876: D0 0B 
C2/2878: 8A
C2/2879: 0A
C2/287A: 0A
C2/287B: 0A
C2/287C: 0A
C2/287D: A8 
C2/287E: A9 09
C2/2880: 99 AE 2E 


(I think this particular instance could be handled with a hex editor but I'm curious as to an asm format.)