These tutorials, many obtained from external sites, might be helpful

Basic TSO / System description, plus naming conventions -- High Level Qualifiers (HLQs)
external image pdf.png TSO and HighLevelQualifiers tutorial.pdf

How to use ISPF -- the mainframe text editor
external image pdf.png ISPF tutorial.pdf

How to create & allocate datasets
external image pdf.png Datasets tutorial.pdf

Some chapters from a book -- basics on how to use a mainframe includes how to use ISPF & HLQs
external image pdf.png mvsbook.pdf