MIND THE GAPPS
We’ve mentioned that AOSP can’t include proprietary Google code; the ramifications of that is that a default install of LineageOS doesn’t offer Google Play services or any associated Google Android apps you might be familiar with, such as Maps, Keep, Hangouts (oh no– Ed), Gmail, and so on. You do get open-source equivalents of some, such as Calendar and Contacts, but it’s not the same if you’re switching, and you’re going to want access to the Google Play Store.
That gaping gap is filled by the Open Gapps project at
http://opengapps.org. This provides a suite of downloads, from a minimal 125MB Pico install that’s the base Google Play services, to a full-fat Super package at 860MB, which includes every app ever shipped to a Google device.
You need to choose the correct platform. ARM is 32-bit (similar to x86), which is most devices out there. ARM64 is for 64-bit devices. These devices and newer are 64-bit: OnePlus Two, Samsung S6/ Note 8, Google Nexus 5X/6P, Pixel 1/ 2. If it offers 4GB of memory, it’s likely 64- bit. If it’s an Intel Atom, you need the x86 build.
Choose the correct Android version for the release of LineageOS you’re installing— probably Android 7.1—then the variant. We recommend Nano, because you can install just the Google apps you’d like once you’re up and running. Avoid Stock, unless you’re running a Google device, as the camera app (designed for the Pixel) can go a bit screwy. If you want everything, choose Super or Full.
We recommend you copy and install this alongside the OS image—you can stack up packages to install via TWRP. If you encounter any odd crashes after LineageOS starts, reboot to TWRP Recovery, and clear the ART Cache and Cache to clear this up.