(suspenseful music) - It was an incredibly challenging experience being out there for the soldiers because not only were they fighting the enemy in the form of the Germans and the Italians, they were also fighting the desert.

(board clicks) (music continues) So we're in sunny, sandy Belfast, which is, you know, the most obvious place to film.

There were conversations about shooting on location, but it was felt that actually a lot can be achieved now through blue screen and through CGI, and actually shooting it in this slightly more contained way would give us more freedom and hopefully not sacrifice the scale, because you need to feel the vastness of the desert.

- [Ahad] The scale at which they've built that set is remarkable.

360 degree view of a blue screen.

- We've brought in approximately 130 tons of sand and rocks and gravel.

We've hired tents, desert Jeeps, and we had to build a cave.

- There are dust bombs raining down on us throughout the series.

- You're breathing it all in and it can get pretty nasty, but I think we're trying to build that world authentically.

- [Meenu] The shooting style has been very much about feeling this impact on their bodies.

You know, the kind of temperatures that they were in, there is talk about sun strokes.

There's an entire sequence in the series where they have no water.

(intense music) (explosion thuds) - When they're loading up the pyros and the explosions and all that stuff, there's a part of you that gets really excited.

- [Jonah] It's great for us because it gives us things to react to and it makes it feel alive and dynamic.

It needs to look real, with the rifles and the (indistinct) and the machine guns and it's quite impressive.

- [Blake] To research the role, watching documentaries and old footage of British troops in North Africa has been really, really helpful, just to kind of get an idea of physically what it was like for the men back then, but also what the training would've been for them as well, I think it's really important.

I found an old World War II training video, which was partly funny because the guy's voice was very, "There you go.

There's Jerry now.

Let's take him down, boys, shall we?"

Very like that, which was like a parody of most things you've seen since.

But to know what their training was, to know what their mindset would be in certain situations, I think it's also really important.

- [Ahad] I haven't done a lot of training with weapons, so it wasn't too daunting to pick up those Enfields the first time.

They are quite heavy and they, and they are quite, quite difficult to load, 'cause those things would jam 'cause we're in the desert.

You get a lot of genuine reactions from all of us because we just can't seem to get it to load.

- What is he doing?

I think some of my favorite moments playing my character as an actor has been the stunts.

Shooting the rifles, ducking for cover.

I had to have a fight with a Nazi soldier the other day.

So being able to have fun doing that has just been really amazing.

(upbeat music fades out)