Bamboo can grow in pretty poor soil, so yours should be happy with what you've got. You could lightly fertilize, but it's not necessary. When I do fertilize, I use a slow release fertilizer like Osmocote, but you can use any well-balanced grass fertilizer as well. Mainly, you need to water well.

The planter sounds fine. Plant it so that the top of the soil in the pot is even with the top of the soil in the planter. The only issue is that Alphonse Karr is a clumper, so it will not spread out in that long bed. Therefore, you may want to get several more A. Karr, or other species of clumpers, if you want the planter to be full of bamboo.