なら sets a condition, often with a meaning of 'if it is the case that'. Unlike ば or たら, なら often has a nuance of 'given that you mention it' or 'in that situation'. For example, if someone says they are going to the store, you might say 行くなら、卵を買ってきて (If you're going, buy some eggs). It sounds like you are responding to something already known or mentioned.

With nouns and な-adjectives, なら is very common: 学生なら、割引があります (If you are a student, there's a discount). With verbs and adjectives, なら works with the plain form: 雨が降るなら、試合はやめよう (If it rains, let's cancel the match). Note that なら does not require a specific verb form like ば does; it just uses the plain form.

One important point: なら is often used when the condition is a premise or a given fact, rather than a hypothetical. For hypotheticals with 'if', ば or たら are more common. But なら is perfectly natural in everyday speech, especially in responses to offers or suggestions.