First you make sure, that the custom textures you want to make links to, already exists in a game-directory.

Then in QuArK, you go into the texture-browser, and choose 'New main folder'.

This will bring up a dialog-box where QuArK asks you, in what .QRK file you want to store the new texture-links.

If you have the textures in a special game-directory, like a TC/PC/MOD, I suggest you choose the option 'In a new Add-on'.

If you already have some custom textures from before, you can choose 'In an already registered Add-on', so you don't end up with multiple .QRK add-ons, but for this tutorial we will select the 'In a new Add-on'.

Now that you have selected 'In a new Add-on', QuArK ask you for a filename. Keep the file in your QuArK-directory, along with the other .QRK files, so you can always find it again.

In the texture-browser tree-view, there will now be a new main folder, called 'New Folder'.

You can rename this folder (and others as well), by highlighting it and press the F2 key (just like in Windows' File-explorer.)

While still having selected the new main folder (now called 'My Custom Textures'), you click on the right-most icon in the menu-bar. The one where the fly-over help is 'make links for a folder of Quake 2/Heretic II textures (.wal and .m8)' . This also works for creating Half-Life texture-links, but unfortunatly not for Quake-1 (I don't know about Hexen-2 and Sin.)

A click on the icon, brings the 'Texture File Finder...' dialog-box up. In this you select the game-directory where your custom textures are located. In this example, I'll choose to create texture links to whatever I have in my Action Quake-2 game-directory.

After a little while, QuArK will show you what textures it have found. If you don't like the structure it has stored the texture links in, you can change it as you like, by moving the links into a different texture-list, or create new sub-folders which will contain texture-lists, etc. (almost just like Windows' File-explorer.)

You create a new texture-list by using the 2nd right-most icon in the menu (if in doubt, always read the fly-over help). The 'new sub-folder' can be found in the 'Folders' menu.

Remember to save your changes, before leaving QuArK! If you forget, all your work will vanish, because your newly created .QRK Add-on have not been saved properly.