There seems to be a book that might help you. The link is below. You will have to pay for it, but it features sheet music for trumpet of many themes, including the work from John Williams. In this collection, "Schindler's List" is featured. This might be a very good starting point for you. It might be a bit more difficult to find the sheet music for the theme online for free. There seems to be many dead links that don't necessarily help you. If you have the opportunity, I would also investigate any music teacher who could help provide the sheet music to you. Along these lines, I think that being able to communicate with other trumpet players could be helpful for you. I have also included a link of someone playing the theme on the trumpet. Listening to it and matching up notes played with what is heard might be very helpful.