Juniper has created some 2 1/2 hour versions of introductory classes. These are recorded webinars that are available for free after registration.
These are the on-demand free Junos Jump Start webinars.
Fundamentals (brocade translation)
This focuses on data center switching applications and translation of Brocade functionality. But is also a good introduction to the switching setup in general.
http://event.on24.com/wcc/r/1406916/7EE0228F66FC153835FBC9A459FF92F1
Intermediate – routing focus
This covers static, OSPF and BGP topics.
https://event.on24.com/wcc/r/1447694/93B98725ECBA4410110E3088F77F1C7A
Advanced – OSPF & BGP Features
This continues the routing focus with more advanced features in OSPF and BGP.
https://event.on24.com/wcc/r/1447732/A3EE6CC09D30C09AA285D970AA4ECD74
Switching
This is basic campus layer 2 switching, STP and related configurations.
https://event.on24.com/wcc/r/1454559/46C09933FB41B796BBB84DA17CD979D4
Security
Introduction to the SRX and the Junos flow module that has full session based firewall and NGFW features.
https://event.on24.com/wcc/r/1479176/D629AFB04B914DADF04978F5B7A9781A
Automation
Introduction to automation with the focus on Ansible and PyEZ as the tools.
https://event.on24.com/wcc/r/1479199/9650330AD93D8A8BCD258923FCA29553