Here's how it's used:
* Je sens: I smell
* Tu sens: You smell
* Il/Elle/On sent: He/She/One smells
* Nous sentons: We smell
* Vous sentez: You (plural) smell
* Ils/Elles sentent: They smell
Example:
* Je sens le parfum des fleurs. (I smell the scent of the flowers.)
* Tu sens bon! (You smell good!)
Important note: "Sentir" can also mean "to feel" in some contexts.