initialize

borg init --encryption=repokey /run/media/kota/sietch/borg

It will interactively prompt for a passphrase. When finished you should backup the passphrase and key in your password manager. Export the key:
borg key export --paper /run/media/kota/sietch/borg

create backup

borg create -s --progress /run/media/kota/sietch/borg::{user}-{now:%Y-%m-%dT%H:%M:%S} ~/docs

or create a script:

#!/bin/sh

export BORG_REPO=/run/media/kota/sietch/borg

borg create                             \
    --stats                             \
    --progress                          \
		--exclude "$HOME/docs/games/*"      \
		--exclude "$HOME/docs/podcasts/*"   \
		--exclude "$HOME/docs/audiobooks/*" \
		--exclude "$HOME/docs/iso/*"        \
                                        \
    ::'{user}-{now}'                    \
    ~/docs                              \
    ~/pics                              \
    ~/music                             \
    ~/g                                 \

borg prune                              \
    --list                              \
    --prefix '{user}-'                  \
    --show-rc                           \
    --keep-weekly   2                   \
    --keep-monthly  2                   \

list archives

borg list /run/media/kota/sietch/borg

extracting is a little funky

Say you just accidentally deleted your favorite artist's folder from /home/kota/music/

You can search a recent archive to see if it's available:
borg list /run/media/kota/sietch/borg::kota-2021-09-25T18:53:21 | grep "Death Grips"

You should see results with paths like:
home/kota/music/Death Grips/Album/file.mp3

Borg's extract command extracts relative to your CWD so your should do the following:

cd /
borg extract /run/media/kota/sietch/borg::kota-2021-09-25T18:53:21 "home/kota/music/Death Grips"

If you're unsure just use the --dry-run option.

Alternatively you can mount a backup and copy the files out manually:
borg mount /run/media/kota/sietch/borg::kota-2021-10-05T21:39:41 tmp/borg