Need Help Explaining Licensing for Vector Use

So, I am trying to make a logo for our school because they are replacing their previous logo. I want to do it using vector graphics. I will be using inkscape. I found that there is a lot of free vectors available that I could use, but am I allowed to use them for our school logo? Can someone explain which kinds I could use, I would how (if I need to) should I give credit to the author of the vector.

Also If it is a simple vector, could I possibly make it myself? Thanks.