First select any dimension and one measure and see the show me. Show me chart will enable based on dim selected.
See my image, i have selected customer segment and sales and my show me enabled bar,treemap,pie,bubble,box and whisker
BI, Aspire Systems (India) Pvt Ltd
If you a date dimension by default tableau will suggest to take line and area charts. Show me will give the suggestion based on the measures and dimension you have selected. Still you can make that reports by doing it manually by following the steps given on tableau online help