Perform tayammun if there's no access to water for purification purposes; Have an intention in your heart that you are performing it as an act of worship towards Allah SWT; Roll in dust if necessary; Strike ground with hands then blow on them before wiping your face & palms with them; Follow Prophet Muhammad's example & teachings .

This hadith explains the importance of performing tayammum, which is a dry ablution, when water is not available for purification. The hadith was narrated by Sa'eed bin 'Abdur-Rahman bin Abza from his father and it tells the story of a man who came to Umar and said he became impure following sexual emission and could not find any water. Umar told him not to pray but Ammar bin Yasir reminded him of an incident where they were on a military expedition and became sexually impure but could not find any water. Umar did not pray while Ammar rolled in the dust then blew on his hands before wiping his face and palms with them. When he told this story to Prophet Muhammad, he said that would have been enough for him to do so demonstrating by striking the ground with his hands then blowing on them before wiping his face and palms with them. This shows that it is permissible to perform tayammum when there is no access to water for purification purposes as long as one has an intention in their heart that they are performing it as an act of worship towards Allah SWT.