When you approach the junction, change down to two and if it is clear then go without stopping. If it's a blind corner or you can't go, stop and put the handbrake on. Change down to gear 1 and find your biting point. With one hand on the wheel and one on the handbrake, lower the handbrake and as you do this put in more gas and keep the clutch at the biting point level. (Biting point is where the car will move if the handbrake is not on, so if you do this correctly you won't roll back).
If you can, try and find a road that is quiet and on a hill. Then just practice pulling off on a hill. It's basically about just using more gas. If you find that you are using more gas but still roll back, then add more gas, then add a little more. If it's still not working, then bring the clutch up a tiny bit (and I meant tiny!) when your handbrake comes off and you add more gas.