docker/bootstrap: Make README.md a bit more detailed

Change-Id: If095b584cd99521770280533359da5024ff745bf

3rdparty/docker/bootstrap/README.md

@@ -1,8 +1,40 @@
 # Haiku bootstrap in a container
 
-1) make
-2) make init
-3) TARGET_ARCH=arm make crosstools
-4) TARGET_ARCH=arm make bootstrap
-5) ```make enter``` lets you enter the container and poke around.
+The Haiku bootstrap process is highly dependant on what tools are installed
+on the host machine.  Bootstraped haikuporter builds can pick up on things
+like the locally installed clang vs the gcc toolchain we are providing.
+
+By running bootstrap within a container, we can better isolate the process
+from the end users host and create more-reproduceable bootstrap builds.
+
+> This is designed for GCC bootstraps. In theory if Haiku changed to clang,
+> the need for a crosstools toolchain is removed... however the clang work
+> is too early to know exactly how this process will work.
+
+## Requirements
+
+1) docker
+2) make
+3) An internet connection
+
+## Process
+
+1) Build the docker container
+
+```make```
+
+2) Check out the required sources
+
+```make init```
+
+
+3) Build the crosstools (gcc only) for your target architecture
+
+```TARGET_ARCH=arm make crosstools```
+
+4) Begin the bootstrap (building Haiku + the required bootstrap hpkgs)
+
+```TARGET_ARCH=arm make bootstrap```
+
+5) If you need to enter the build environment, ```make enter``` will quickly let you do so.
 6) profit!