There are seven kinds of obligatory ceremonial baths:

(i) Bath for ceremonial uncleanness (Janabat)
(ii) Bath for menses (Hayz) (for women only)
(iii) Bath for lochia (Nifas) (for women only)
(iv) Bath for Istihaza (for women only)
(v) Bath for touching a dead body. (vi) Bath for a dead body.
(vii) Bath which becomes obligatory on account of one's having taken a vow or an oath to perform it.

But...

 A person becomes ceremonially unclean (Junub) by two things:

(i) Sexual intercourse and
(ii) Discharge of semen, whether it comes out when one is asleep or awake, or it is in a large or small quantity, or it comes out with lust or otherwise, or it comes out voluntarily or involuntarily.

Optional alternate method as demonstrated by the Islamic Prophet Muhammad :

Washing both the hands up to the wrists.

Wash the private parts with the left hand and remove dirt or filth from the body.

Perform wudu (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..

or by Sunni's...

Start by making niyyah (intention) to perform Ghusl, say bismillah (in the name of Allah) and cleanse yourself of impurities.[3][11][12]

Wash the right hand up to and including the wrist (and between the fingers) three times, then similarly for the left hand.

Wash the private parts and remove dirt or filth from the body.

Perform Wudu as if for prayer. Ensure that the mouth and nostrils are thoroughly rinsed three times. If sitting on a stool or stone while bathing then the feet should also be washed when performing Wudu. But if sitting in a muddy place, feet should not be washed at this stage.

Water should be poured over the head three times so that it flows all over the body, ensuring that the roots of hairs and parts not easily reached by water such as the back of the knees are washed thoroughly.[3]

Pour water over the both shoulders three times each (starting from the right shoulder). Hands should be passed all over the body when water is poured so that no part of the body is left dry.

Move to a clean spot and wash the feet if not washed during Wudu

As at the end of Wudu, it is recommended to recite the Shahada....

Do not do these while you are not clean

The following five things are unlawful for junub:

(i) To touch with any part of his body the writing of the holy Qur'an or the Names of Almighty Allah in whichever language they may have been written. And it is better that the names of the holy Prophet and Imams and Lady Fatima Zahra (peace be on them) should also not be touched in that condition.

(ii) Entering Masjidul Haram or Masjidun Nabi, even though it may be only entering from one gate and going out of another.

(iii) To stay in all other Masjids except Masjidul Haram or Masjidun Nabi, and similarly, on the basis of obligatory pre- caution, to stay in the shrines of the holy Imams. As regards the Masjids other than Masjidul Haram and Masjidun Nabi, however, there is no harm if a person enters through one gate and goes out of another

(iv) To go and place something in the Masjid, or to enter or take out something from it even from outside.

(v) To recite any one of those verses of the holy Qur'an on the recitation of which performance of prostration becomes obligatory.

These verses occur in four surahs of the holy Qur'an: (i) Surah Alif Lam Mini as-Sajdah, 32:15 (ii) Surah Ha Mim Sajdah, 41:98 (iii) Surah an-Najm, 59:62 and (iv) Surah al- 'Alaq, 96:19.