Need support to generate chart with date picker in Qlik

Im new to Qlik and need support to create a chart from a date picker. I’m loading a table from a database, which have these attributes: id, date, username, duration
Unfortunately the date field in the datepicker is empty. I was expecting to select 'date' as datefield.
First task: date should be selectable in datepicker
Second task: generate chart (x-axis is username and y-axis is duration)...the Chart will show the duration for each day by a user.