How to define an artboard size with Axure?

I'm a totally newbie with Axure, so I apologize if my question sounds like "obvious" to those who are used to use the tool.

I'm familiar with tools where we set an artboard before starting to create something. Currently, Adobe XD is my main bet on that. I've browsed on Axure and I couldn't find where at least see on which size I would start to work. So, if I wanna make a wireframe for a website (could be 1920 w), how can I limit the area to 1920 to avoid putting content outside the artwork (our "artboard" on Adobe XD) ?

I searched a lot on Google and Youtube but I didn't find that specific answer. I've looking for some wireframing-targeted tool (prototyping too) and since companies, for some reason, consider Axure as their "little darling", I decided to at least understand its essentials, I mean, the main stuff to get the thing done as quick as possible. If you also could recommend me some best practices working on Axure, I appreciate.

Thank you!