Selecting value from auto complete field is little hard if you are not aware about proper key sequence technique. Just "type" command will not provide you list of value suggestions on auto complete field. "sendKeys" command will provide you list of value suggestions on auto complete field but to select valuefrom that drop down, you need to use "keyDown" command in selenium IDE.
"keyDown" command works like user is pressing keyboard key but not releasing it. You can press any key of keyboard using "keyDown" command. You need to provide single character or ASCII value of any key into value column of "keyDown" command. Let me give you an example.
In above example, 1st “keyDown” command will open related keyword suggestion drop down for character “a” by pressing down arrow key. You need to use ASCII value (“\40”) of down arrow of keyboard in value column. 2nd “keyDown” command will select first value from suggestion drop down. 3rd “keyDown” command will move value selection to one step down. In this way, 5th “keyDown” command will select 4th value from suggestion drop down. Last “keyDown” command will press enter button(“\13” is ASCII value of “Enter” button of keyboard) text box will be filled with last selected value. In this way you can select value from auto complete text box drop down. Try above example practically to get it better.