The creation process of Private and Public campaigns is almost the same. Details regarding Private campaign creation you can find here.
When you choose the Public campaign type you see this first step.

You can also place the campaign globally to make it applicable for all other marketplaces.
After the summary continue with fulfilling the brief, mood board, and select needed social channels.
The next step is to select influencers that will be invited to participate in the campaign. All predefined criteria will be automatically applied to the search and the result will list only valid influencers. This step can be skipped at all because this is a Public campaign and Influencers can apply by themselves. 

Once you have finished with the basket of potential participants you get to the Campaign preview page with the whole data on our campaign.
If you haven't finished any steps the wizard won't let you start the campaign - all required fields have to be filled in. Missed fields will be marked with an exclamation mark as a sign which steps lack the info.

Click Invite and Run (or Run the Campaign) to finish with Campaign creation.
If you invited influencers during the campaign creation flow you can also see Projections of results.

Go to Campaign page -> Details tab and review projections.