it gives a seed?   haha as far as i know your backup the wallet the same as BTC's electrum wallet, as lbrycrd is a fork of BTC and the app is an electron one
they have instructions at https://lbry.io/faq/how-to-backup-wallet, but its basically ya just like any other coin, save your wallet file!
i believe LBRY is a bit more complicated with claims, but the wallet file holds the coins keys, so its #1