The DLS computers have iMovie installed and ready to use for your class or personal projects. If you want more control, you can use Premiere Pro in Adobe Creative Cloud, which is also already installed on the DLS computers.
Access Adobe Premiere Pro tutorials here.
You may want to look for footage to use on Academic Videos Online (AVON) or Kanopy, both of which are available through the library's databases. There are tutorials for accessing these databases in this guide.