I've inherited a JIRA with that people have been poking at for seven years, with dozens of obsolete projects, workflows, etc. and thousands of tickets. For example, I'm having trouble setting up a Kanban board, because too many issues get pulled in by default. I've never administered JIRA before, so I'm groping my way through the complicated configuration and 'it depends' documentation.
Can anyone recommend a guide to paring down a JIRA that hasn't been managed well?