Here’s the guide you can get to know how to use the built-in tools like pencil for candidate markings. In which, you can get to know about highlight errors, or reveal to show the correct number for a selected square.
On the other hand, you can use-solve, use strategies like tracking candidates' pencil marks for using each cell.
Here’s the steps to follow
Go to your puzzle following its official link
Use the pencil toll to write down all the possible numbers for a blank cell
You can use check tool to highlights incorrect numbers
Use the reveal tool to choose square and click reveal to get the correct numer
Also, you can go with hit tools to the next solvable squared without giving away the answer directly.