All modules will vary, but it is suggested that you aim to have between 1 and 4 module units of learning. (elearningindustry.com)
These will be structured units of learning, which are designed to be delivered to learners via electronic means. (growthengineering.co.uk)
Much the same as a hiker entering the woods, when students begin a project or unit of learning there should be trail markers along the way. (edutopia.org)