No such thing as a dumb question - of you don’t ask a question, you miss a opportunity to learn.
You could use the FollowMe tool built into Sketchup. Or Fredo’s Round Corner plugin.
If you are making a small box, make it into a component, make a copy and scale it up, then work on the enlarged copy, so rounding the corners doesn’t try (and fail) to make very small edges.
@DaveR has posted numerous examples on the forum about this.
See also the links to videos in this thread