고서

Having done that, then

Joins two actions and stresses that the first was finished before the second began: filled a cooler box with ice creams and then, put on the national team jersey and then, turned the GPS off and then found those places. Plain 고 also means 'and then', but 고서 leans on the completion. Two other shapes to know: 지 않고서는 means 'without doing it', and 고서야 means 'only after doing it', as in realising the flavour only after half the pack.