I cant install Xposed in Lollipop 5.1

Hello, my name is tito. I wanted to know how to install the xposed framework for Android 5.1. I've downloaded the apk, i've downloaded the zip files, i tried to use twrp recovery to flash the files but i cant install it. I choose the most recent version, then i go to install and it downloads the file, then it give's me a message saying: Ensure the partition listed below is the correct one for your device. If you do not verify this then you risk bricking. On some devices it is impossible to flash recovery while in android. If flashing doesn't work for you then please flash recovery a different way. /dev/block/bootdevice/by-name/recovery. And it give's me two options: NO-YES. If i choose no, it doesn't do anything, if i choose yes it says me: Please wait: Flashing and recovery or something like that. Then it give's me an error saying: Something is wrong: Flashing recovery was unsuccessful. Either you already have this recovery installed or another error has occurred. Would you like to attempt rebooting to recovery now? If i choose CANCEL it doesn't do anything, if i choose OK it reboots my device and it appears the android logo with a warning icon on him. I thought my phone was broken. I turned off it and it tried to turn on it again, and thanks god that it wasnt broken. I've tried a lot of things. My phone is an LG Leon (NOT LTE) (Its rooted) and i suspect that the reason of this is that this app makes me say to it what phone i have, and i pick LG Leon LTE because there isn't anyone that says only LG Leon. Please help me. I just want to have the Xposed installer. When i had kitkat it was pretty easy. I've never used this things of rom's and custom recoverys, i dont understand anything of that. I made a Nandroid Backup. I have BusyBox installed. Can this be happening because i dont have the bootloader unlocked? If it's that please explain me how can i unlock it, because there's not too many tutorials about my phone. If theres another way to install Xposed Installer, or there's another custom recovery i can use, please tell me.

Thank you all. Tito

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