There is no one fixed position or angle that will be a perfect fit for everyone. So try the Olive with different ear tips. A couple of pointers to try to find the right position and the right ear tip.
a. When you place the Olive with the ear tip in your ear. It should fit tight within your ear. You might feel a bit uncomfortable with the new ear tips. It takes a while to get used to.
b. As much as possible, ensure that the ear lobe is not obstructing the path of the microphone from collecting sounds. Wear it as shown in the figure below. Ultimately, find the best position that suits you.