A page begins with a lead section which is a summary of the page. The lead is the part before the table of contents and the first heading. It should explain the topic, why the topic is important, and the summary of the most important parts. The importance of the page's subject is explained in the first few sentences.
A lead section looks like this:
|Selena is the first studio album by American singer Selena. It was released on October 17, 1989 by EMI Latin. The album was recorded in San Antonio and Houston, Texas. The album was Selena's first album to be released by EMI Latin. She signed a record deal with them earlier in the year. Selena got to number seven on the US Regional Mexican Albums chart. By 1996, 24,000 copies had been sold. The album helped Selena to win "Female Vocalist of the Year" and "Female Entertainer of the Year" at the 1990 Tejano Music Awards.
The lead section is followed by other parts. See the Wikipedia:Guide to layout. It is not good to begin a page with only a heading.
The lead section should not have citations in them, because the information should be in the rest of the article somewhere, and citations in the lead section makes the lead section harder to read.
Use lead tags when either the lead needs to be fixed, or re-written, or is not there.