Some people don't really know what takes to be a Muslim, just like the Christians are baptized to be born again, Muslims also have a ritual bath to become a full-fledge Muslim, it is called Ghusl.

Ghusl is often translated as "full ablution", as opposed to the "partial ablution" of wudu وضوءthat Muslims perform after lesser impurities such as urination, defecation, flatulence, deep sleep, and light bleeding.

The Ghusl is done once after you have converted to Muslim but it needs to be done again after the following happened 

Sexual Intercourse or Ejaculation (Al Ghusl Janabat). Yes you read that well, when you have wet dreams you are required to perform Al Ghusl Janabat. 

Menstruation ( Al Ghusl Hayd)

Virginal Discharge after birth ( Al Ghusl Nifas) 

Here are the guidelines to perform Al Ghusl

There are three obligatory acts. If one of these acts is omitted, it must be returned to and completed before the remaining acts.

Rinsing the inner mouth. 

Sniffing water and blowing it out.

Washing the entire body.

Washing both the hands up to the wrists, then wash the private parts with the left hand and remove dirt or filth from the body, perform ablution, pour water over the head three times, and rub the hair so that the water reaches the roots of the hair. Then wash the body, making sure that the water reaches all parts, starting with the right side of the body and then the left and rubbing it with the hands so that the water reaches the entire body.

You are done with your Ghusl and welcome to becoming a Muslim.