Uminom is about drinking something non-specific...."I drank some water." (Uminom ako ng tubig.) Use "inumin" for something specific..."I drank your water." (Ininom ko ang tubig mo. Ininom is the past tense of inumin.) There are the conjugations and a bunch more example sentences here: https://www.tagaloglessons.com/words/uminom.php https://www.tagaloglessons.com/words/inumin.php