It is useful to know how to make a box, without having to do it by trial and error. Believe me, there can be a lot of error involved!
You start with the basic size of your box. In my case a 10 cm square. To get the size you need to cut, you need to add twice the depth required to the length of each side. So, in my case, 10 cm + 2cm + 2cm = 14 cm. So that is the size square I drew to start off with.
Next, I drew some 2cm squares. They need to be the size of your box depth. I used the knife tool (on solid setting) to cut one diagonally to make two triangles.
After proper alignment, the triangles are subtracted from the corners of the large square. Then horizontal and vertical score lines are added. To make a lid, I duplicate it and then with all of it grouped, scale it to 102%. In most cases this is enough to allow the lid to fit over the box. Do remember to label the top or bottom - if you want to make a plain base but cut out the wrong one, it will be a waste!
If you wish, you can add a circle to each side of the lid and subtract (modify window) to make finger grip placements, like this
To get all the details, watch the video linked at the start.