Firstly, open the link followed:
Secondly, download the gz file named "L4.1.15_1.1.0_LINUX_DOCS " in the Recommended Documentation.
Thirdly, unzip the file and follow the file "Freescale_Yocto_Project_User's_Guide.pdf" to build a Yocto image and use MFG_TOOL to download to the i.MX6Q SABRE-SDB. The MFG_TOOL is named “IMX6_L4.1.15_1.1.0_MFG_TOOL(REV L4.1.15_1.1.0)” in the Programmers (Flash, etc.) which attached in the following link:
(PS: The MFG_TOOL contains the built Yocto image, So you can directly step to Thirdly to run MFG_TOOL to download the Yocto image to your i.MX6Q SABRE-SDB.)
All the best
You can get the documentation from this link:
User guide (how to install), release notes and multimedia docs for your linux installation