Follow the clearly marked signs to Heathrow Express.
Take the Express to London Paddington Underground station.
Follow signs to the District Line which is the green line on the Underground maps. Board the train to Wimbledon. From door-to-door, the entire trip should take approximately 35 minutes.
Follow the signs to the London Underground or "Tube," as it's loving called in the UK.
Use the Piccadilly Line (designated in blue on the Underground maps) to Earls Court Station.
Change onto the District Line, which is the green line on the maps.
Board the train to Wimbledon. Your entire trip should take one hour.