Dw, Wiki is like 90% correct these days. Only pages you should watch out for are the controversial ones. ten Hag's page without looking is probably 99% reliable.Just looked on wikipedia (yes, I know...)
'Following his retirement, Ten Hag took on a coaching role at Twente's academy, initially overseeing the U17 team, followed by the U19 team until 2006, when he was promoted to assistant manager. He worked under Fred Rutten and later Steve McClaren until 2009. He then joined PSV, working as an assistant under Rutten once more.[5]'