Mark questions or sections for students

That's what the coaching function is for. You just need to become their coach.

I'd show you a guide but I'm currently using a tablet so I can't, but since it's one of the main features on Khan Academy it should be easy enough to find. If not, there's probably some form of guide.

Hi Nishant, if it's math questions you can recommend exercises to your children using the coach tools as Ayaka alluded to. First you must set your Roles to include Coach under Settings, and change your Home page to Coach. Then you create a class (you may want to create one for each child.) Once you've put your children in the class(es) you can Monitor their activity

You also have the ability to recommend math exercises.

If you want them to do videos or non math exercises you cannot make recommendations directly to your children on KA. The only way to do that is for you to create a CS program, give your children the url, and write the list of homework in the program. Frankly, for home schooling it's much easier to grab a piece of paper and a fridge magnet : )

(volunteer Star Guide)