I'm confused on when to use "y" or "e" for saying "and" in Spanish. Can someone please explain

Y becomes e when it precedes a word that begins with the i sound. Typically, y becomes e when it precedes most words that begin with i- or hi-. O becomes u when it precedes a word that begins with the o sound

Explanation:

read the following texts. text 1 electoral marketing consists of implementing integrated political marketing and social communication techniques, in order to gain the approval and sympathy of the society, building a solid image of the candidate and being able to transmit reliability and safety to the population by raising its concept at the level of public opinion. therefore, electoral marketing is concerned with the formation of the image in the short term. catarin, roberto bianchi. electoral propaganda in media democracy: the victory of emotion in the 2014 presidential election in brazil. 2016. dissertation (masters in communication) - school of communication, education and humanities, methodist university of são paulo, são paulo, 2016 (158 p.)