This is the most common scenario. Select MONTHLY BACKUP as the schedule, and INCREMENTAL BACKUP as the type. On the calendar that is displayed, select every one of the 31 days, and down further, there should be a checkbox for doing a FULL BACKUP as the first backup of the month.
That will give you what you wanted. Now, the reserve strategy is something additional. That strategy says how may backup cycles (i.e. months) you should keep before starting to recycle the older backups (to save space on your backup device).
EaseUS Todo Backup user - volunteer non-support forum moderator