Wood St station is on the Weaver Line which runs from Liverpool St station in London. It is one stop after Walthamstow Central. You can also go to Walthamstow Central by bus or on the Victoria Line tube, then change to the Weaver Line.
Meet outside the station by the bike shop. Postcode: E17 3LX
You can go back to Wood St station if you wish very easily, but an alternative is to continue through Walthamstow village with the guide and down to Walthamstow Central train and Underground station, there is also a bus station here.