On the Insert tab, click the Table button in the Tables group. In the drop-down menu, select the small boxes that represent columns and rows and select how many rows and columns you want in your table ...

In Microsoft PowerPoint, you don't need to create a table style from scratch; instead, learn how to apply a style and tweak it to get quick, professional results.

You can manually create a custom Gantt chart from scratch using the native Chart menu of PowerPoint. In its Chart menu, you can find several types of standard charts including line, bar, area, pie, ...