First of all, LineageOS must be supported by your device. You can try to look for your device here. Here I am going to install LineageOS on a Redmi 8A device.
First, unlock the bootloader and then follow these steps for this specific device. Here is a YouTube video that may help to understand the process of installing LineageOS better.
Things to keep in mind
- Update the ADB and Fastboot to the latest version.
- Your device should contain sufficient charge.
Helpful command
Here are two commands that maybe be helpful while working with adb.
adb reboot fastboot this command will boot your phone into fastboot mode.
fastboot reboot recovery this command will boot your phone into recovery mode.
From here you can download all the default apps of LieangeOS: https://www.apkmirror.com/apk/lineageos/