Hey Starfish,
First off, realize that as much as some would like to forget it, all of us have been newbies and NONE of us knows it all. Every diver I have ever known has something that just shows how green they were, and sometimes, how green they still are. Its OK to be a newbie.
Second, most backplate & harness systems have "optional" pockets that can be threaded onto the waist belt. You can also accessorize with D-rings and other items that will enable you to load yourself down with whatever you want to carry. However, please follow the general rule of less is better, unless you are tech diving or cave diving, where redundancy counts, redundancy counts!
However, you should also realize that FEW people (I have yet to see one, save my first instructor)dive with tables on their person. You might have a note board clipped to your BC to record your time, and your depth guage will probably have a max depth indicator. Still, before I owned a computer, I simply dialed in my Dive watch to the time I went down, and noted the time mentally when I went up. I was never off but by a minute or two, and I would record the info once I got topside. I would then work out my dive profile to figure out if I were a "W" diver or not (grin). As for PLANNING, I always asked the dive boat operator how deep I should expect, and then I consulted my tables to see about how long I could go down for. I also checked the next lower level just in case he was in error, and remembered that number too. In my 122 dives, I have yet to dive outside of my limits. However, the last seventy or so dives have been with my Cobra. Still, my tables stay in my dive bag.