Clarify creation of downloads dir

Author: arthurbarr

docs/building.md

@@ -8,7 +8,8 @@ You need to ensure you have the following tools installed:
 ## Building a production image
 This procedure works for building the MQ Continuous Delivery release, on `x86_64`, `ppc64le` and `s390x` architectures.
 
-1. Download MQ from IBM Passport Advantage, and place the downloaded file (for example, `IBM_MQ_9.0.4.0_UBUNTU_X86-64.tar.gz` for MQ V9.0.4 for Ubuntu on x86_64 architecture) in the `downloads` directory
+1. Create a `downloads` directory in the root of this repository
+2. Download MQ from IBM Passport Advantage, and place the downloaded file (for example, `IBM_MQ_9.0.4.0_UBUNTU_X86-64.tar.gz` for MQ V9.0.4 for Ubuntu on x86_64 architecture) in the `downloads` directory
 2. Run `make build-advancedserver`
 
 > **Warning**: Note that MQ offers two different sets of packaging on Linux: one is called "MQ for Linux" and contains RPM files for installing on Red Hat Enterprise Linux and SUSE Linux Enterprise Server.  The other package is called "MQ for Ubuntu", and contains DEB files for installing on Ubuntu.