Welcome friend, welcome. Another member is always welcome.
What you need for the grapple depends on what you are starting with. If you already have the front end loader then it becomes a fabrication job, either do it yourself or buy. There's all kinds of different designs out there, depending on what you want to do with it. Some designs are slightly better for one thing and another is better for something else. You'll need another set of hydraulic outlets in addition to the FEL's to control the opening and closing of the grapple. Apart from the control lever/diverter on the tractor itself, that's about it.
I got mine when I bought my Kubota L4740 new. I got the FEL and bucket but also had a guy at the dealer fabricate the grapple for everything that I wanted to do with it. I will admit that it may not be the sexiest or prettiest thing in the world but the son-of-a-gun does work. In fact, in the 3 years that I've had the tractor, I doubt that I've had the bucket on half a dozen times. The grapple stays on there all the time. It's just so friggin' useful. It's a combination of brush puller and grabber, log skidder and dragger, round bale mover, crane, hydraulic jack, post puller and setter, demolition tool (sometimes on purpose & sometimes not) and just about anything else that you need brute force for. For a long time, I thought that the FEL and bucket was the most useful thing I'd ever run across but it's second on the list.
I don't know if that was of any help but I hope so.