It is good to undergo premarital checkup. Since you are healthy otherwise we are performing only those tests which are essential to determine if you can lead a successful married life, that is, be able to have proper sex and make children. If you have ED prior to marriage, be it however you diagnose it, needs full evaluation. Basic testing is done in PMC. Detailed testing will require further tests. Sperm analysis is performed to make sure you do not have surprises after marriage. You should note that even if sperms are normal some women may not conceive and it can be due to many reasons. You should have an idea of basic structure of penis, erection, vagina, foreplay, sexual intercourse and how to perform. You should also have a basic idea of conception. The male should be able to deposit semen deep inside the birth passage of his wife. Semen should stay in the vagina for at least 4-6 hours before it can ascend through the uterus and reach the tube to meet the egg. Egg is released around 9 days of completion of periods (for 5 days bleed usually). The concept of fertile period is important and it can vary from person to person and sometimes between cycles. A safe estimate is to have alternate day sex roughly around the same time from day 7 or 2-3 days after bleeding has stopped and continue for at least 12-14 days or till onset of bleeding.