How to generate Concurrent User load in Jmeter

I have a test where users will logs in and enter search keyword in search field and will get the results. Finally logs out.

Now I want to test concurrency using Jmeter. So this is what I came up with.

Test plan
  Thread group
  + Login request
    + Synchronizing Controller
  + Search string 
    + Synchronizing Controller
  + Logout 

I have added 10 in number of threads. I have added 5 in Synchronizing Controller. So when I run the test I will get the concurrency of 5 users? Rest 5 users will be simultaneous users?

Also I have depended request when login page loads. So to achieve concurrency on login, I have added all the request in transaction controller and added Synchronizing Controller as child to transaction controller. Please let me know if I am doing it right.

Also please let me know if there is another way to achieve concurrency for specific action (ex: 5 users hitting login button at same time).