I've done about 10 of these, passed a few of them too. I'm not gonna lie, it's something you'll probably have to do a few times before you get properly used to the format unless you happen to come across really well over the phone (I don't).
Assuming like all mine it's competency based then the format will be as follows:
1) Why this company?
2) Why this scheme?
3) STAR questions.
I'd advise you look up The STAR method online if you're not familiar with it. They'll ask you something leading like "Tell us about a time you've led a team?" then you have to refer to an example in your life where you've adequately demonstrated that skill.
My advice is to come up with at least 10 base examples of times you've shown teamwork skills, influence/networking skills, motivation etc.
The chances are even then you could end up floundering looking for a decent example. If worst comes to worst just bend the truth a bit to fit the narrative, but don't outright lie, that'd be pointless.
As I say, it takes a few goes to get good at this, don't be disheartened if you fail, I applied to literally 100 jobs before I found something really good in banking. I failed, bombed and messed up more times than I care to mention, it's perseverance that will get you to where you want to be.
Good luck!