You can use a database maintenance plan or you can use a script to backup and schedule is for every two hours.
Here is an example:
Management-> Database Maintenance Plans-> New Maintenance Plan-> Choose the Database->
Uncheck the backup and then check the transaction log.
Click on the schedule button and then set it up to the time of your liking.
Example 2:
Do the following:
Management-> SQL Server Agent-> Jobs-> New Job
Create a job and include the following script in steps:
BACKUP LOG MyNwind
TO MyNwind_log2
Create a schedule under schedules:
Schedule the job at the appropriate time.