You can learn a lot from just listening to films, listen to how it's layered together I like to start with the backgrounds, then sound effects, foley and finally dialog. Ask yourself why they used that sound, how does it make you feel or what do you think it's trying to convey, this can help you when editing sounds together to tell the story rather than just the "See a Sound Cut a Sound" approach.
If you own a Digital Audio Workstation I guess the best thing you could do is look for a scene in a Movie, TV Show or Game Cinematic and redo all the sounds, there are sites like FreeSound and Sound Bible to get access to free SFX's, also a lot of companies and independent sound effect recordists like to give away some of their sounds for "free" if you check their websites (Blastwave FX, Boom Library, Hiss and a Roar and Hart FX). Also there are books like David Lewis Yewdall's "The Practical Guide To Motion Picture Sound 4th Edition" & "The Game Audio Tutorial" by Dave Raybould & Richard Stevens that provide Sound Effects for you to learn and practice with, they even have websites with loads of resources. Especially on David Yewdall's book-site there's so many great videos to learn from on there. One thing to keep in mind is that these may be free but make sure you read and know all the legalities of what your allowed to do with the sounds you get. Welcome to the community and all the best.