Showed the way job's secured in design originally (10)

'showed the way' is the definition.
The definition and answer can be both to do with communicating as well as being past participle verbs.
Perhaps you can see a link between them that I can't see?

'job's secured in design originally' is the wordplay.
'job' becomes 'post' (post is a kind of job).
'secured in' indicates putting letters inside.
'originally' is an anagram indicator.
'design' is an anagram of 'signed'.
'post' placed into 'signed' is 'SIGNPOSTED'.

Can you help me to learn more?