Assigning effect to muliple samples

[newtoFL]

Sorry for asking all of the questions, but I couldn't find the answer to this but I read it somewhere before. Anyway, I am using FL Studio and was wondering how I could assign an effect to multiple samples at once. I would also like it to use that effect on one part of the song in a breakdown. I assume I would create an automation clip for that but not sure how to add that in the middle of a track since the effect will not be applied the whole time. Thanks