You should be able to transfer the os installer into an 8+ gb thumb drive via DiskMakerX. You do need a working mac with something that works with the mac app store installed and enough space to download the os from the app store. Afterwards, just boot up your mac with the alt key, and install.
I understand this is probably a noob question, but can somebody explain what is preventing anybody from swapping a 128GB SSD for a 256GB?
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