There are several implementations of the BitTorrent peer-to-peer file sharing protocol. Transmission is only one of them. After installation (opkg install transmission-daemon) there should be a config file in the uci directory.

A few more details about configuration file (/etc/config/transmission) can be found here.

opkg update

Daemon is a program that runs in the background and is designed to not have any form of visual interface

opkg install transmission-daemon

CLI (Command Line interface) is a "normal" torrent client designed to be run from a text based console

opkg install transmission-cli 

Transmission has a web interface which can be used to monitor and manage your transfers over the internet

opkg install transmission-web

transmission-remote to control Transmission through RPC (remote procedure calls) with a GUI on the host machine.

opkg install transmission-remote

To enable Transmission at all, put option enable 1 into /etc/config/transmission.

If you want to start Transmission on boot, run

/etc/init.d/transmission enable

To start Transmission, run

/etc/init.d/transmission start

If you wish to use the web server, besides installing the package (see above), you might need to whitelist your IP address (if it is not in 192.168.1.0/24) via option rpc_whitelist '127.0.0.1,192.168.1.*,your_ip_address'. By default, the server listens on port 9091.

To controll transmission remotely via RPC, install Transmission Remote GUI and set it up just like the webserver above.

There is only one section: /etc/config/transmission.

config transmission
        option enable 1
        option config_dir '/etc/transmission'
        option alt_speed_down 50
        option alt_speed_enabled false
        option alt_speed_time_begin  540
        option alt_speed_time_day 127
        option alt_speed_time_enabled false
        option alt_speed_time_end 1020
        option alt_speed_up 50
        option bind_address_ipv4 '0.0.0.0'
        option bind_address_ipv6 '::'
        option blocklist_enabled false
        option dht_enabled true
        option download_dir '/mnt/sda4/'
        option encryption 1
        option incomplete_dir '/mnt/sda4/incomplete'
        option incomplete_dir_enabled false
        option lazy_bitfield_enabled true
        option lpd_enabled false
        option message_level 2
        option open_file_limit 32
        option peer_limit_global 240
        option peer_limit_per_torrent 60
        option peer_port 51413
        option peer_port_random_high 65535
        option peer_port_random_low 49152
        option peer_port_random_on_start false
        option peer_socket_tos 0
        option pex_enabled true
        option port_forwarding_enabled false
        option preallocation 1
        option proxy ""
        option proxy_auth_enabled false
        option proxy_auth_password ''
        option proxy_auth_username ''
        option proxy_enabled false
        option proxy_port 80
        option proxy_type 0
        option ratio_limit 2.0000
        option ratio_limit_enabled false
        option rename_partial_files true
        option rpc_authentication_required false
        option rpc_bind_address '0.0.0.0'
        option rpc_enabled true
        option rpc_password ''
        option rpc_port 9091
        option rpc_username ''
        option rpc_whitelist '127.0.0.1,192.168.1.*'
        option rpc_whitelist_enabled true
        option script_torrent_done_enabled false
        option script_torrent_done_filename ''
        option speed_limit_down 100
        option speed_limit_down_enabled false
        option speed_limit_up 40
        option speed_limit_up_enabled true
        option start_added_torrents false
        option trash_original_torrent_files false
        option umask 18
        option upload_slots_per_torrent 14
        option watch_dir_enabled false
        option watch_dir ''

• Transmission performs much better when swap is mounted.
• Besides CLI and WEB UI see also Transmission Remote GUI.