It's an amazing start! Are they English Budgies? They look a little big...
It's a pretty good sized cage for three, but the bar spacing looks a little big? I don't know the recommended spacing for English Budgies, but bar spacing American budgies should be no wider than 1/2".
I'd personally recommend using the grate in the cage. Especially with three birds in there. It's very important to help keep the birds and their droppings separate. It is a bit more work when you have to clean the grate and the tray, but it's just more sanitary.
I love all the natural branches! It's great! My only thing is that dead-end perches are best. It basically forces your bird to be active, so they can't just walk from one end of the cage to the other.
There are some really good toys in there! I would take out the ones with rope on them. Toys are meant to be destroyed, and if your birds like the rope one, they can ingest the little rope fibers. Those then can get stuck in the crop and cause an impaction. The rope perches are fine, as they don't have any loose ends. Just keep an eye on them and remove them if you see your birds chewing on them.
There is also a lot more room in the bottom half of the cage for toys and perches. Encourage them to use all the space provided in the cage!
I would also suggest putting food and water on opposite sides of the cage. It just helps keep things cleaner.
Over all, it's pretty great!