diff --git a/README.md b/README.md
index c2d5bcc..c24ea12 100644
--- a/README.md
+++ b/README.md
@@ -10,15 +10,22 @@ It assumes UFW for now.
 
 - For a.b.c.0 and a.b.c.1 you will get a block on a.b.c.0/31.
 - For a.b.c.0 and a.b.c.255 you will get a block on a.b.c.0/24.
-- You will also get a block on a.b.0.0/16, if there are at least 4 blacklisted IP blocks on the form a.b.z.0, for any z.
+- If there are at least 4 blacklisted IP blocks on the form a.b.z.0, for multiple values of z, you will also get a block on a.b.0.0/16.
 
 ## Building
 
-The easiest way to build this is to use Docker.
+### On a Linux machine.
+
+- The Dockerfile shows which tools and libraries are needed, even though in your particular Linux distribution the packages may be called something else.
+- Then go to the src directory and run `cmake .` and `make`.
+
+### On a non-Linux machine.
+
+Here we use Docker.
 
 1. Install the Docker command line client on your machine.
 1. Run `./build.sh`. This will build a binary for aarch64 or x84_64, depending on your host.
-1. You can also add the parameter `arm` or `x86` to the `./build.sh` script to build for a particular architecture.
+1. You can add the parameter `arm` or `x86` to the `./build.sh` script to build for a particular architecture, if your host machine supports that.
 1. The result will be a binary in the `bin` sub directory.
 1. You can then run `./run.sh` for an interactive environment. In this case the full repo will be copied to new `repo-x` directory (where `x` depends on the architecture), so your changes do not disappear when the Docker container exits. This script also takes the parameter `arm` or `x86`.