It depends when you're going, there are trains at 23 mins past at Stortford to Tottenham Hale, 7 minute wait there for train to Stratford. Stratford to Heron Quays on the DLR 13 minutes, trains every 10 mins. eg. 09:23 Stortford- TH 09:48, 09:55 TH - Stratford 10:07, 10:14 Stratford - HQ 10:27.
Otherwise you need to go into Liverpool St and either out to Stratford or get to Bank and take the DLR from there.