I have taken and I took are almost the same. I took is passed tense. I have taken is simple present perfect tense. You would say I have taken when the action is still in process, but really the two function as almost the same. I took the pill, and now we will see if it works. I have taken the pill, and now we will see if it works. I took her to the airport this morning. I have taken her to the airport and will be back soon. Hope that helps!

Today I take my books to the library. Yesterday I took my books back to the library. Have I taken my books back to the library? Yes, I have.