Off the top of my head...
Go to
https://reshade.me/ and download the latest version (3.0.8) -- Don't bother with Reshade 2 or SweetFX or EDFX or anything that doesn't use 3.0. The main thing with 3.0 is you can preview everything in real-time.
Run the installer you just downloaded. Press the big 'Select Game' button, and find your elitedangerous64.exe (not edlaunch.exe).
It'll prompt you to download a set of shaders. You can untick everything but the 'SMAA' one if you don't need anything else. ReShade initialises faster if you have less shaders to load at startup.
Then you have to click on the 'Direct 3D 10+' option below the 'Select Game' button and you're done with installation.
Start up ED. You should see a gray bar at the top of the screen and a message that ReShade is loading.
Press shift+F2 to open ReShade's menu and run through the tutorial.
From the list of shaders, enable SMAA. You can play around with the settings from there. When you're done, go to the Settings tab at the top of ReShade's menu and change from 'Configuration Mode' to 'Performance Mode'
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You'll need to repeat the above every time the game gets updated. I recommend that you create a folder called ReShade in the root folder of your C: drive. Then, in ReShade's menu, click the + button to create a new preset, and type the full path to save the configuration outside of ED's folder... so for config name, enter something like C:\ReShade\SMAA.ini (after you've created the ReShade folder)
If you do it that way, you don't have to worry about losing your configs when the game upgrades. You just re-type the path to that preset config after re-installing ReShade and adding a new preset again. You can even enter it during the tutorial to save time.
Edit: make sure to disable AA completely in ED's graphic options as well.