Fleshed out the README with more instructions.

README.md

@@ -5,9 +5,12 @@ This attempts to match the build process used by [`cibuildwheel`](https://github
 
 - For `manylinux_x86_64`, we create a Docker image based on `quay.io/pypa/manylinux2014_x86_64`. 
   These have HDF5 and friends installed in a standard location and should directly work with `find_package()`.
+  This should be used with the `CIBW_MANYLINUX_X86_64_IMAGE` option.
 - For `musllinux_x86_64`, we create a Docker image based on `quay.io/pypa/musllinux_1_1_x86_64`.
   These have HDF5 and friends installed in a standard location and should directly work with `find_package()`.
+  This should be used with the `CIBW_MUSLLINUX_X86_64_IMAGE` option.
 - For `macosx_x86_64`, we build binaries using the `macosx-11` runner.
-  These binaries can be downloaded and unpacked to a location specified in `CMAKE_INSTALL_PREFIX` for `find_package()`.
+  The resulting tarball should be unpacked to the `installed` directory, which can then be set to `CMAKE_INSTALL_PREFIX` for `find_package()`.
 - For `windows_x86_64`, we build binaries using the `windows-2019` runner.
-  These binaries can be downloaded and unpacked to a location specified in `CMAKE_INSTALL_PREFIX` for `find_package()`.
+  The resulting tarball should be unpacked to the `installed` directory, which can then be set to `CMAKE_INSTALL_PREFIX` for `find_package()`.
+  Note that MSVC builds should define the [`H5_BUILT_AS_DYNAMIC_LIB` macro](https://www.hdfgroup.org/downloads/hdf5/).