Have you used the forum search feature, magnifying glass icon, upper right and reviewed the various discussions on installing Transmission to the second gen v2.x single bay My Cloud units?
Here are a couple of discussions to get you started. Please not that Transmission IS NOT supported by WD on the single bay My Cloud units.
https://community.wd.com/t/wd-mycloud-gen2-enable-apps-install-tab-apps/177885
https://community.wd.com/t/wd-mycloud-gen2-chroot-transmission-and-minidlna/148686
https://community.wd.com/t/my-cloud-gen2-easily-install-transmission/176459
