Questions about the first Democratic presidential debate are swirling ahead of Wednesday’s qualifying deadline.

Only 20 candidates will make the stage for the June 26-27 debate, which will be spread out across two days with 10 candidates on each night.

It’s unclear who will debate whom, or how the Democratic National Committee (DNC) will make some of its final calls on the placement of candidates. The DNC has not announced when it will disclose the final list of 20 debate participants, but one campaign source said it could come Friday.

The deadline to qualify is midnight Wednesday and candidates have until 11 a.m. Thursday to provide certification to the DNC.