It’s often good to use external design rules such as the JLCPCB design rules. Here’s how to import the JLCPCB design rules
Go on to this website and download the appropriate design rules for your project. Select the appropriate rules for the amount of layers you are using and the weight of copper and download that. For the onboarding project it’s the (2 layer 1 oz copper .RUL file)
Click on design → rules and open the PCB Rules and Constraints editor
Right click on the design rules folder → import rules
Press “ctrl + A” to select all rules in the dialogue that follows then press ok to then import the .RUL file you downloaded.
You will get a message saying “clear rules to import?” Select ok then the rules should have been imported