Light coating of powder is good. Don't get on too steep or too flat of a run. Start on your toe edge (that the edge that your toes point to). Get on your knees (!!) slide down on your toes and adjust the edge to control speed. Do NOT let your rear edge touch, if you do let it touch hopefully you have a helmet on because you will probably end up catching the edge, coming back and hitting your head. As you do this you can use your hand to push off the ground or to hold you up to feel out that edge. Do that for a while just kind of adjusting your weight from your left and right legs to adjust which direction you will go.
Now do the opposite, sit on your butt and stand up adjusting your weight to keep the weight on the heal edge, again allowing weight to transfer from left to right leg. It is actually easier to go on the heal edge when just standing on it. After you get a feel for that, start to point the board downhill but don't do that for too long, maybe 5-7 feet and then go back to the full heal edge. Go straight and slow yourself down, go straight, slow yourself down. Etc etc. Keep your edge to slow down, practice allowing your left foot to go first as you are on your heal edge and then straighten it out and go right foot first. This will allow you to turn by sliding left to right (or vice versa). Once you get that go ahead and do the same thing but on your toe edge. Toe edge is a bit trickier because if you catch an edge you fall backwards. If you catch that toe edge you will face plant be careful not to catch yourself with your hand, it is bad for the wrists and that's how they end up broken. Use the forearm...
Hopefully that helps. A paid lesson is always a good start.