Converting, will be more expensive then buying a new trials bike,
i,e you need to change the wheels and tyres, as the mb setup is usually to skinny
single speed kit
i would buy better brakes and a lower seat setup
and change forks to rigid
but none the less, this is all too pointless as with mb frames the geomotry is wrong and the frames are usually too high
so your best bet is to buy a new trials bike completely
hope this helps