Selenium dynamic locaters

Problem :- 1)i am unable to locate the customer at step 6. Its not a dropdown and when i click on the button i am unable to select the customers.
How to chose the customer dynamically at step 6.
2) while creating tasks how to fill the data All the elements are dynamic as Id keeps on changing.
Attaching my Java file
Scenario-
Website- https://online.actitime.com/mindtree60/login.do
1. 1. Login to actitime.
2. Validate the home page.
3. Click on Task tab.
4. Click on Create new task.
5. Validate Create Task pop window is opened.
6. Select Customer. -
7. Select project.
8. Create 5 task at same time with different type of work.(Here element properties will be changing during run time)
9. Click on Create Task.
10. Validate task has been created.
11. Logout.