To tell time in Spanish, you can follow these guidelines:
1. Use "es la" for the first hour (one o'clock). For example, "es la una."
2. Use "son las" for all other hours (two o'clock onwards). For example, "son las dos."
3. After the hour, add the minutes using "y" (and). For example, "son las dos y cinco" means "it is two o'clock and five minutes."
4. To express half past the hour, use "y media" (and a half). For example, "son las tres y media" means "it is three o'clock and thirty minutes."
5. To express a quarter past the hour, use "y cuarto" (and a quarter). For example, "son las cuatro y cuarto" means "it is four o'clock and fifteen minutes."
6. To express a quarter to the next hour, use "menos cuarto" (minus a quarter). For example, "son las cinco menos cuarto" means "it is a quarter to five" or "it is four forty-five."
7. You can also use "faltan" (lacking) to express the time remaining until the next hour. For example, "faltan diez para las seis" means "it is ten minutes to six."
These are the basic expressions for telling time in Spanish. Keep in mind that the way time is expressed can vary from region to region, so it's always good to double-check if you are unsure.