Problem with Attributes

Hello all,  I'm starting a new camping with roll20, but my players are having problems in the character creations wizard. Whey they get into attributes, the only option is Custom. How do i make the other options appear in there. Like random attributes. Thank you

Unless you have purchased the Players Handbook, that is your only option. Believe it or not, the SRD (freely available rules that Wizards makes available under the Open Gaming License) does not list how to roll for ability scores. Therefor, it cannot legally be placed in the charactermancer. Most people use a custom macro, like: Str=[[4d6kh3]] Dex=[[4d6kh3]] Con=[[4d6kh3]] Int=[[4d6kh3]] Wis=[[4d6kh3]] Cha=[[4d6kh3]]

Does it worth it to buy the players handbook? I want to GM the Descent to Avernus campaign.

Buying the players handbook is most useful if you are using the D&D5e by Roll20 sheet and the charactermancer. It makes it possible to utilize the full range of character creation options through the Charactermancer. You could of course, do it all manually, but the PHB is a worthwhile purchase.