I don't have the actual setup for that myself, so I don't know exactly where the links are supposed to lead, but you should find all the pdf's inside your CC3+ data directory (The directory you chose during installation, default is c:\ProgramData\ProFantasy\CC3plus). Most of the guides are sourced from annual material, so they'll probably reside inside the Annual subfolder, while I guess the compendium itself is probably in the Documentation subfolder.

Note that since you say "start learning", if you're not familiar with CC3+ at all, the best place to start is with the manual, which also contain many tutorials. You can access this from the help menu.

Change house layer should be able to be used at any time (in a city map). But it is only useful if you wish to use the demographics coloring of buildings in CD3, apart from that, it isn't really that helpful.

For the step by step:

1. Activate change house layer from the city meny
2. Select the buildings to change layer for (Finish selection with right click -> Do it as usual)
3. CC3+ now prompts you for the layer. You can type it in, but the easiest is to right click to bring up the dialog, pick the desired layer, and click ok.
4. All done

Yea, I meant fixed. That's what happen when you type from memory.

The memory cache keeps bitmap images in memory instead of reading them from disk, which makes the loading faster. The -1 default size automatically allocates half the available memory, although I am uncertain if this is half of the max memory CC3+ can address [4GB] or half the system memory, I need to ask the developer about that. If the former, then you could potentially get some performance by increasing it above 2GB, but that really only helps if CC3+ needs that much memory (see the currently in use value). Increasing it if CC3+ doesn't need it won't help with anything.

To force the highest quality (Not normally required) just click :CC2RESMODE: and set it to Manual - Very High

That would be the Like modifer (F2). Just press F2 after selecting select by color (or fill style or line style, etc) and CC3+ should ask you to pick an entity to take the property from.