Where should I start?

Learning how not to ruin and lose your gear while applying what you already know about fishing, combined with a unique set of simple skills that only apply to kayak fishing, will fast lead to highly productive results.  It’s not just rods and reels that don’t last and just “disappear”. What Howie and I lost in sunglasses alone would still buy a few kayaks today and add everything from locksmith bills at the beach (lost keys) to electronics and tackle boxes loaded with lures, stuff floating away……it was a brutal indoctrination and we weren’t the guys who could just go out with one stick, a few lures and some bait.  BTW, that’s a great way to get started.  Give yourself a chance to grow into your gear and try not to buy stuff like sonar, hundred dollar kayak seats and $200+ reels before you get a feel for fishing your particular model.  Look at what other anglers in your fishery have done with their (same model) kayaks and if you have an application that could compromise seaworthiness (not limited to bait tanks and anchor riggings), get advised.