more backpack et al info needed

ok, i am a beginner, you all know that. I got some great info before in my last post about back packs, and i thank everyone for their time. Now i have obtained a Black Wolf Buggaboo back pack which suits both me and my budget. Macpac was the aim but my mortgage supplier told me where my heart truly lies.......
Now this back pack has all the gizmos, buckles, straps, d rings. Now i can see that most of the straps and buckles are for tightening and stopping things from flopping around but there are a few thingos i dont full understand, but will work them out in the long run. If anyone else has one or has seen them, any info or advice would be most grateful.
Now, when i was in the Army, we had what we called basic webbing, which consisted of water bottles, bumpack and ammo pouches. Water bottles were shaped to contour roughly to body shape. All i can find in hiking stores are round aluminium bottles. Are they better than Army plastic ones and where do you put them? i hate the idea of things swinging in the breeze and they dont seem to fit anywhere due to their shape. Speaking of which, they come in all sizes, is bigger better? i have read a few websites about packing backpacks and no-one mentions waterbottles
Now this back pack has all the gizmos, buckles, straps, d rings. Now i can see that most of the straps and buckles are for tightening and stopping things from flopping around but there are a few thingos i dont full understand, but will work them out in the long run. If anyone else has one or has seen them, any info or advice would be most grateful.
Now, when i was in the Army, we had what we called basic webbing, which consisted of water bottles, bumpack and ammo pouches. Water bottles were shaped to contour roughly to body shape. All i can find in hiking stores are round aluminium bottles. Are they better than Army plastic ones and where do you put them? i hate the idea of things swinging in the breeze and they dont seem to fit anywhere due to their shape. Speaking of which, they come in all sizes, is bigger better? i have read a few websites about packing backpacks and no-one mentions waterbottles