1) Download the release. See
https://streamlink.github.io/install.html for where to find it on your platform.
2) Extract the release somewhere, I put it on a secondary drive.
3) Find the "bin" folder withing the location you extracted it to, this will be where the executable lives.
4) With a command line (search "CMD" in windows, choose "command prompt"), make your way to this folder by changing drives (if necessary) and "cd"ing into the "bin" folder.
Changing drives, to do so type the drive letter and a colon, then hit enter. You should see the text on the left of the cmd window change to the drive you just entered. For example:
Hit enter and assuming you have an E drive the text on the left will become
E:\>
indicating you are now on the E drive.
To move between folders, use
cd
, for example:
If there is a directory called "streamlink" from wherever you execute that command, would attempt to change where the terminal is running from to be within the "streamlink" folder and then the "bin" folder within the "streamlink" folder. This is not as complex as it sounds since you can use the "tab" key to cycle between available locations with cd, for example if I'm on the E drive, and there's a twitch folder on E, if I type
cd
(note the space after "cd") and then hit tab, it will cycle through all available items on E. If I type a letter after cd, like so
cd s
and then hit tab it will cycle through available options starting with s.
In windows, this is not case sensitive, almost all other platforms will be case sensitive.
Once you have the correct directory selected with tab, you can type a "\", and the "\" will denote to start looking in the folder behind the "\" (so in this example the "streamlink" folder), in which case tab would find the example "bin" folder next since that, for the purposes of this example, is the only folder in the "streamlink" folder.
Being in the right folder is important as this will determine how hard it is to run commands, in the case of the code I'm providing, it assumes the CMD is sitting in the streamlink\bin folder which is where streamlink.exe resides, so if you aren't sitting in that folder the code won't work quite right.
5) Once you have the CMD window in the streamlink\bin folder, the code above will work, but make sure you set the absolute path to the file to a folder that actually exists, so continuing the example, let's say you want to store the recordings in a theoretical "E

twitch\harleyplays" folder; make sure that the theoretical
E:\twitch\harleyplays
exists, if not, make those folders before you start playing around with the commands. The hypothetical path to the file for the above command would look something like this:
Code:
-o E:\twitch\harleyplays\{id}-{time:%Y%m%d%H%M%S}.ts
That bizarre shit in front of the ".ts" is replacement values, so it should generate a file that is named like "twitchId-yearmonthdayhourminutesecond.ts", obviously with those time based values being based on when the command executes. This will prevent accidental overwriting of previous recordings.