A Gantt chart is a timeline of a project. Each task within a project is given a duration which is indicated by the length of the bar. Gantt charts are an easy and helpful way to visualise your PhD project and allocate time to different tasks. You must include a Gantt chart in your Confirmation Review submission, and your supervisor may ask you to update your Gantt chart periodically.
There are many different pieces of software you can use to create a Gantt chart. The most simple is Excel, but Microsoft Project is designed specifically for project management. You can also use Lucidchart, Asana and various other systems. You need to find the one that works best for you, and that allows you to visualise your research clearly.
A simple Excel Gantt chart is attached below, which you can use as a starting point for creating your own time management plan.