Just a box, then you can use one of the extensions I mentioned. I'd start with this one:
https://inkscape.org/en/~Neon22/%E2%98%85lasercut-tabbed-boxHere are instructions for installing an extension:
https://inkscape.org/en/learn/faq/#how-install-new-extensions-palettes-document-templates-symbol-sets-icon-sets-etc Be sure that Inkscape is closed while you install it.
Next, open Inkscape, then look for Extensions menu > Render > Lasercut Box (or something close to that).
From there, I can't tell you exactly what to do, because I've never used it (or even installed it). If you get stuck, I'll install it so I can help you. But at least give it a try on your own, first.
I expect it should be fairly straightforward how to use it. I imagine it will have a place to enter the Width, Height, and Depth. I wouldn't be surprised if you can choose how wide you want the glue flaps. If it's very sophisticated, if might offer different kinds of closings, whether you just tuck in the flap, or it gets glued shut, or something else.
When you finish entering the numbers, then click Ok (or the button might be called something else, like maybe Submit, or Create, or something). Then after a few seconds, it will show up on your screen. Then just save the file.
You might want to contact the company that's going to cut out the boxes, to find out what kind of specific requirements they might have. Like if something gets printed on the box before it's cut out, the printer might want a specific file format. Or the cutter might want a certain format, besides SVG. Or there might be something else they want. Just find out what they want, and if Inkscape can do it, we'll tell you how.
Let us know if you get stuck and we can help