Herman,
Are they just buds? Tight little nubs that will become candles? Or have they grown and have needles? If just buds, leave them be for now. Wait 'till late spring or summer so you see what's growing, and what direction you want the branch to grow, or wire it out to, and pick twigs accordingly.
Remember with white pine, you only get one flush of growth per year. No decandling. Usually, we only get one or two active tips to work with, so if you have a choice, that's great!
Very often, with white pine, there's no need to pinch the candles back, because they grow so slowly. Sometimes, you may get really strong candles that overgrow the design, so you can pinch those back before they've hardened off. We call that 'candle breaking'. Be sure to leave needles on any pinched candle.
Fertilizer? Usually not in the spring. Wait until the candles and needles have hardened off in early summer. Then start to apply fertilizer. This keeps the tufts of needles tight. Fertilizing too soon causes the twigs to get 'leggy'. (Unless you are really pushing for growth. If you are, then fertilize in spring to encourage as much growth as possible.)