Below are a few more details on the templates:
Much content is posted on this site, on Reddit and other websites but few look like typical FFG products, and the main reason for that is the use of tools and the involved amount of work.
If you were asked to recreate a marble statue but only given a hammer and a single wide chisel, the result might be close but really hard to match perfectly. The same is true for the Star Wars books. They are put together within a typical publishing workflow that is based on the Adobe Suite of products.
The key product used is InDesign. This is Adobe's solution for all desktop publishing and has become the market standard in many areas. The problem with InDesign is that it is fairly expensive. There are old versions out there that will work just as great. Alternatively, Adobe has a 30 day trial which is usually more than enough to turn one fan product around. There are alternatives (e.g. Scribus), but they are incompatible with the provided templates, however, you can still use the provided assets.
The other key product is Photoshop, especially to change / adapt pictures to make them fit into the product. GIMP is a great alternative, but also comes with a learning curve. The trickiest part to recreate are the images and their "feathered borders". You can find plenty tutorials how to achieve this effect, so I won't go into too much detail here.