Well that sounds great so far.
Make sure you introduce any veggie slowly and one at a time, to see if it affects your bun badly. Start by introducing different veggies, until your bun has tried many and is fine with them. Make sure you check a safe fruit and veggies list too. Do this over a few weeks, I would recommend, monitoring poops and tummy and behaviour etc.
If she is absolutely fine with them (no runny poops, gas etc.) then I'd start by giving her a cup of a variety of chopped veggies every day. Try and alternate them each day. So day 1 give her a few chunks of carrot, a handfull of spinach, romaine lettuce and a few chunks of cucumber, and then day 2 give her a handful of kale, a few stalks of broccoli, 3 or 4 big chunks of celery and some parsley.
If she is fine with these and wolfs them down, then maybe try another cup or so.
Make sure to monitor her weight and how much hay she is eating (she still needs to eat looootss of hay).
If she is staying a healthy weight, eating lots of hay and eating all her veggies and pellets, why not add a few fruit treats every few days? Mine get a few chunks of apple, then a few days later maybe a chunk of strawberry and a chunk of banana etc.
You just need to (by trial and error) see how much (and which veggies) your rabbit can have. All rabbits are different in regard to this. Some buns can eat all veggies all the live long day (mine do lol) and be absolutely fine. Some buns can only handle a few chunks. Some can't eat any at all without getting runny poops and gas.
Mine get 1/4 cup pellets each, unlimited timothy hay, and a big salad of lots of veggies and some fruit each day. I try and give 4 or 5 different veggies each day.
Also there are some veggies you might need to be careful of, as they have been known to cause gas in high quantities, or contain a lot of oxylates (what these do I am not sure); kale, mustard greens, collard greens, broccoli, cauliflower, sprouts etc. Also buns cannot have ANY tomato GREENS (the stalk etc.) or apple pips, stones etc. or anything from the onion family at all OR potato- I believe this is actually a part of nightshade family. I am not sure why the flesh of the potato can't be eaten, because I believe it is only the greens of those vegetables in the nightshade family that cannot be given (eg. tomato greens). Apparently peppers are part of the nightshade family, so I would steer clear of the pepper stalk! Not that I have given that to my buns anyway. In fact I am going to make a thread on this. Also carrot is quite high in sugar so you might want to be slightly sparing with that; mine get perhaps 1.5- 2 carrots a week and maybe some people might think this is too much.
hope this helps!
Jen