[Q] MAJOR NOOB needs help with using my external SD for apps and data topic

So I have looked around XDA-Developers for at least 3 hours now over the past few weeks (most from work!), and I am still absolutely lost when it comes to fixing my L9 P769 ((running JB 4.1.2 (SW Ver P76920h)) so that I can install apps to my ext. SD card.

I have read multiple forums and posting, and I am convinced that you all KNOW what your are doing, but I still can make sense of your posts enough to fix my own phone. Can anyone PLEASE explain this in as much detail as possible, step by step?

I am not as big a NOOB as some (I have flashed ROMs to 5 different phones over the years) BUT I still can't get this one figured out, and the last thing I want to do is screw up the phone I need for daily communication.

My wish list for this phone is not that long.
1) Apps to my Ext. SD
2) ability to communicate with a heart rate strap (I think I need BT 4.0, but I read somewhere that it could be done with this phone.)
3) Maybe make my phone a little faster (OC of CPU? what does overclocking the GPU help with?)

I'd rather not put a new ROM (.kdz?) on this phone, unless it's FLAWLESS. I have a very low tolerance for glitches, in my old age!

Thanks for any help and all replies!

macdofco
LG L9 P769 (rooted/locked bootloader(?))
16GB SD card
T-Mobile (unlimited 4G Data !... actually only 3.5G, lol)