The first thing is to unlock the bootloader:
Step two is to install recovery mode but before doing this you need to change the date because if you do not do this you will not be able to flash recovery, you will receive this message: Only Official Released Binaries Are Allowed To Be Flashed, so follow the steps in the video and change the date:
Link for recovery that works: twrp-a51-3.5.0_10-1_ianmacd
Assalom-o-Alaikum! How to Root and Flash TWRP on Samsung Galaxy A51 One UI 2.5 Android 10 CTJ1 Build number- Android security patch level: 1 October 2020. It may be work for SM-A515F, SM-A515F/DSN, SM-A515F/DS, SM-A515F/DST, SM-A515F/DSM...
forum.xda-developers.com
Link for how install recovery anf instal lineage metod, is the same:
Now flash lineage OS, app-pakagearm64 nano vresion and magisk 21.2 last stable vresion(update to 21.4 from magisk manager before!!!)
There is a system bag before setup/oppen phone that tells us that "a problem has appeared on the device, for details contact the manufacturer", you do not know exactly what it is but it does not affect, problem number 2 is that the fingerprint does not work ... if you try to set your fingerprint will not be worth it and the fingerprint image will remain on the screen everywhere in the menu where you navigate until the phone is restarted!!
The rest works, I hope to follow updates to solve these problems