Updated user-guide

[mikeldking]

The user guide needs to be re-fined to include:

• datasets
• experiments
• template tracking

[Jgilhuly]

Added some extra experiments info: https://app.gitbook.com/o/-MB4weB2E-qpBe07nmSL/s/ShR775Rt7OzHRfy5j2Ks/~/changes/814/user-guide

This is more of an iterative improvement. I can do a ground up rewrite instead if we prefer