To create log book entries form multiple volunteers at one, use the "Add Hours" feature.
You can access this from the left menu or the right-click of your mouse.
Select the records that you want to create hours for.
Then use the button or right click to Add Hours.
First decided what to do if a volunteer is not already placed:
Then select the opportunity:
Enter Start Time and End Time. The tab to the "Hours" field and the system will automatically calculate the time:
Chose the Date:
Then Save (or check Create Another and Save to create multiple entries):