"Gathering" things means going somewhere, getting the things, and putting them all together in one place. Physical things that people "gather" include:
But it's actually more common to talk about gathering information. The idea is similar; you search in different places, find information, and put it all together. For example:
I did an Internet search and gathered some information about different models that we could go with.
We were able to gather names of over 50 different companies in the area that we can approach about advertising with us.