Ok
I will describe how this is normally done when the textures folder containing your home made fills is located within the CC3+ installation folders. With any luck you might be able to work out anything that you need to do differently if you have them stored elsewhere.
1. Open CC3+ and the map where you want to use the fill.
2. Click "Tools/Import bitmap fill styles" from the menu bar.
3. Use the Browse button in the dialog box that opens up to locate the textures you want to import, and double click any one of the textures in that folder to tell CC3+ "These are the ones I want".
(I have chosen one of the folders in my "Sue" folder, so that you can see how CC3+ automatically constructs the path syntax in the box at the top of the dialog)
Import fill 1.jpg
(In the case of storing the textures separately to the original CC3+ installation path as you appear to be doing, I am unsure which of the three path options you should be using, but the default is the top option - "relative to CC3 path", which is the one that I use every time)
4. If this is the first time you have imported this set of fills into a CC3+ map you will need to tick the "Create other resolutions" tick box, and decide whether the fills you are importing are High resolution, or Very High resolution. Most people leave it set on Very High. The fills in the album you linked to in your first post are extremely high resolution (some would say unnecessarily high) by CC3+ standards, where the size of a Very High resolution fill is normally around 1000 - 1500 pi square.
5. It is up to you if you want to set a scale for the fills as you import them, or set the scale individually through the Fill Style Properties dialog after importing them. Whichever way you choose to set the scale of the fills it is an adjustable variable that can be altered at any time by the user.
6. When you click ok and the dialog box disappears there will be a short wait while CC3+ creates the other resolutions for each fill, and imports them into the map (a shorter wait if this step can be skipped if this is not the first time you have imported this set of fills). When this is done CC3 will let you know how many fills have just been imported, which is the signal that it is ok for you to continue mapping - using the fills you have just imported.
And that's all there is to it.
I hope that you are able to use this basic description. I think the only issue you may have a bit of trouble with (where I won't necessarily be able to help you) is at point 3, where the path to the fills is decided.