In concurrency thread group we have many options like

• Target Concurrency i.e total no of users we want to add to our application
• Ramp –Up period- time in which all users should be on website
• Ramp up Step Count-In how many steps all users should be on website.like if we put it 3 –and if we put total number of users as 60 then 20 users will jump on the site in first burst then wait for some time then next 20 will go and then in last burst the last 20 users will hit the website.
• Hold target-For how much time we want these users to remain on site.