Click a day to add an event, drag horizontally to open the breakout dashboard, and drag an event to move its target date.
Adding an event
Hover a day on the calendar strip to reveal a "new event" affordance, then click it to create a new event — a project's target date — on that day.
Opening the breakout dashboard
Drag horizontally along the calendar's timeline to select a date range. Releasing opens the breakout dashboard for that range, summarizing it with a donut chart and line charts. See Reading Everview's Charts for how to interpret what it shows.
Moving a target date
Drag an event to a different day to move that project's target date. The first time you move a given event, Everview records its original date so you can see how far it's shifted since.
Hold Ctrl (or Cmd) while dropping an event to move its target date and reset the recorded original date to match — use this when the new date should become the new baseline, rather than showing a "moved from" history against the old one.
What to do about it
Use a plain drag when you want the history trail (how far a date has slipped from its original plan) to stay visible, and Ctrl+drag when you're deliberately re-baselining a date and don't want that history carried forward.