Before starting this tutorial, heres two differences: using bridges is to hide your connection to Tor from ISPs.
Using a proxy would be to completely anonymize your connection to Tor with proxychains for example.

Step 1: Edit torrc file

  • sudo nano /etc/tor/torrc

Step 2: Add theses lines

For a HTTP proxy
  • HTTPProxy / HTTPSProxy host[:port]
  • HTTPProxyAuthenticator / HTTPSProxyAuthenticator username:password
For a SOCKS proxy
  • Socks4Proxy/Socks5Proxy host[:port]
  • Socks5ProxyUsername username
  • Socks5ProxyPassword password
For a TCP proxy
  • TCPProxy protocol host:port
For a bridge
  • UseBridges 1
  • Bridge [vanilla/obfs(3/4)/snowflake/meek] IP:Port [fingerprint]