XDCC tl;dr

XDCC is basically a file sharing method done through a client, almost like torrent.
Here's the short version for how to download stuff through xdcc
Note: to be clear, "input "xxx""
means type or paste "xxx", then press enter

1. Download and install an IRC client that is usable for your machine.
Just google something like "IRC client for windows 32bit". I'm using HexChat for example.
You need Visual C++ Redistributable for Visual Studio 2015 as well (or probably just for hexchat)
Choose "Normal installation" to be safe.

2. Find out the name of the server and channel that you need to join.
e.g. for anime you can join #[email protected] or #[email protected]

3. Open the IRC client, you'll be prompted what nickname to use and what server to join.
For the examples above, the server name is Rizon and Xertion.

4. A popup will appear. Pick "Join this channel". Input "#NIBL" or "#kametsu" for the examples above. Usually the "#" is already typed in.

5. Find out the command line that you need to input to get the file you want.
Some of the ways to get the command line needed:
- Go to a bot parser website. Usually the channel or the release group will tell you the parser site, if they have one.
- Input "!blist" in the message box and you'll be sent with a text file (if they have one) containing filenames and their respective filenames
- Input "@find searh_term" or "!s search_term" so you'll get message(s) that tell you file(s) that match with your search, and their respective command line. e.g. If you input "!s exil kekkai Ep07", you might get
--------------------------------------------------------------------------------------------------------------------
Sending Results... To stop results /MSG ooinuza STOP - Full Listing at: http://nibl.co.uk/bots.php?search=exil+kekkai+Ep07
[339M] [Exiled-Destiny]_Kekkaishi_Ep07_(DAF47AE5).mkv /MSG NukuServ|Archive XDCC SEND 21884
[339M] [Exiled-Destiny]_Kekkaishi_Ep07_(DAF47AE5).mkv /MSG E-D|Mashiro XDCC SEND 8284
from -ooinuza-
--------------------------------------------------------------------------------------------------------------------

6. Input the command line "/msg bot_name xdcc send XXXX" that you got from one of the method listed at number 5. A popup will appear to prompt you where to save the file.

7. Once the download has finished, you'll see "DCC RECV 'file_name' from Bot_name complete [xxx cps]" in the current chat log.

If the file has CRC in their filename, don't forget to check for CRC, to be safe and sure.

FAQ:
Is it resumable? | Yes
Android app? | Try AndroIRC
Is this chap knockoff of discord? | It's more like the predecassor actually. This method of file sharing have existed way before bittorrent.

Disclaimers:
This is done to promote XDCC method of downloading for people like me in the past, who's too lazy or clueless about XDCC.
I'm still new with this XDCC thingy as well, so I might not be able to help anymore than typing this guide. Try asking for help in channel that has XDCC bots
Just like torrent, speed is dependent on the generousity of the uploader.