Mew, who until recently was assisting Craig Davis at Fleet Town, succeeds Matt and Stuart Hussey at the Millers Park helm.
He will take with him his former Romsey assistant Stuart Long and physio Dave Penny and is expected to add a coach to his backroom staff in the near future.
“We had quite a few people apply and it was a very difficult decision, but we felt Wayne was the ideal choice with the contacts he has. He knows the Wessex League inside out,” said T&E’s vice-chairman Andy Tipp.
“He did a brilliant job at Romsey and we were very surprised when he left there. He worked with no budget there but brought in some very good players.
“Another important factor for us is that we’ve got a very small staff off the pitch and Wayne will be bringing in some experienced people behind the scenes.
“We’re a family club and we need people who will muck in and help out. That’s what local football is all about.”