Whether you're looking to improve your work efficiency or you need to track your time for billing purposes, you can use the time tracking feature easily.
Log in to your account and click your company name drop down
Select "Time Tracking"
You can sort your timelines by time spent, name of timeline, last updated, or start date.
Clicking on an active timeline here will take you to the edit view for that timeline.
Clicking on the time tracked for a timeline will give you a detailed report of which team members spent how much time on that timeline.
Here's a quick tutorial: