When calculating a relative date, such as finding a date 3 months in the future from 20th February, several steps can help determine the desired date. Firstly, establish the current date as 20th February. Next, add 3 months to this date to move three months into the future. For February, March, April, and May would be the future months. Adjust the year accordingly if the future date extends beyond the current year. By manually counting the months and days from the given date, 20th February, and applying this method, the future date 20th May can be determined. This process involves understanding the concept of adding months accurately to yield the correct date.