Conditional
It is best interpreted as “if you are talking about…, then…“, as it emphasises the topic. Overall, なら(ば) is used to give suggestions or advice, speculation, or requests .
〜なら cannot go with the ます conjugation.
食べ~~ます~~なら 食べるなら
Adding the 〜ば makes it moreformal. アリスさんが言うならば、問題ないよ。 In the event that Alice says so, then there is no problem.
Advice or suggestion
中国に行くなら、{万里|ばんり}の{長城|ちょうじょう}を見みてください。 If you're saying you're going to china, please be sure to see the great wall!
カメラを買いたいなら、秋葉原に行った方がいいです。 If you're saying you want to buy a camera, you should go to Akihabara.
いいえ、売り切れましたが、{自由席|じゆうせき}ならあります。 No, they're sold out, but if you would like an unreserved seat instead, they are still available.
if that is the case
it can be used very similarly to から, except that it has a slightly more hypothetical vibe
それなら話は早い。 If you're saying that is the case, then it should be nice and easy.
みんなが行くなら、私も行く。 In the event that everyone goes, then I will go too!
also very often used with a single thing; often names or pronouns. Emphasises that because it's this person, (...), similar to こそ.
悲鳴：こんな難しい宿題全然作り上げられないよ 返事：君ならできる You can do it, because it's you! (lit. If it is you, you can do it)
Request
知っているんなら、教えてください。 If you're saying you know it, please tell me!
with explanatory の
used with the explanatory の・んだ , のなら・んなら is stronger and enforces a confirmation of the content of the condition.
仕事を終えたのなら、帰っていいよ。 If you're saying you have finished working, you can go home.
https://imabi.org/the-conditionals/