[noun] + を経て、[sentence]
を経て goes after a noun and means "after going through it": a process, a stretch of time or a place lies between where something started and where it ended up. It is the て-form of へる経る "pass through", and it is formal – news, reports, speeches, biographies.
The noun is usually a stage that shaped the result: negotiations, trials, interviews, years of work. A plain "after" with no sense of passing through a stage is のあと後で.
With a place name, を経て is "via", the stop on the way to somewhere else. In speech you would say けいゆ経由で.