How Do I save Illustration as a Jpeg as it's normal size?

Hi there, I'm really struggling here

I am going to print these off in a little while as an A1

I set this up as a JPEG for me to print.

The left picture shows the way I want it to print out. The right picture shows the results I got from changing it to JPEG. The pictures are tiny and its just all white around it.

I went on to file, Export then changed it to JPEG. Then it turned out like that.

How do I get this to be the same size as before? On photoshop it seems really simple. But I'm just really stuck.

Please help. thanks