It depends on what type of laptop you have and whether or not it supports to mirror and use as external display, it will not work. So in order to use dex on your laptop, You'll need a laptop that supports mirroring and Acts as external display. For Note 10 it is said that it is supposed to work dex by just using USB C cable and later on will come to devices S10 model and S9 model.
If you've found my post to be helpful, please like the post. If my response resolved your issue, please press the "✓ Accept as Solution" button.