So, pretty fresh to D&D and D&D Beyond (joined from the Critical Role craze, go figure). I want to try out and do tests with some of my characters in combat encounters since I'm not in any current games and I want to see how my characters would play. However, the combat encounter beta will not let me use any of my characters, because of the way the campaign builder works. Apparently, I can only use the characters of people linked to my campaign (which is zero, whatcha gonna do?) and not my own. I don't think this is a major issue all things considered (I do think the encounter beta is not bad, feels like it needs some time in the oven), but I do think that not being able to use your own characters in campaigns you run as a DM (either testing combat encounters or a necessary evil of using DMPCs.) would be beneficial. Those are just my two cents, I'm curious what others think and if that would be something that would be considered in the future.

You just need to put your own characters into a campaign. Create a campaign and use the “join link” to add your own characters to that campaign.

I just tried your advice and it worked. I'll be honest, I feel really dumb right about now for not figuring that out myself, but hey, better to learn from the mistake than not. Thanks for the assistance.

No need to feel dumb, that kind of thing confuses lots of users. Happy to help.