I need help (step by step) moving my photos and videos from my Dropbox ion my iPhone 5s to my PC using Windows Vista. please use step by step phrases. My phone has stopped some of its functions.

I Have too many videos and photos on my phone and my phone is not functioning properly because of it! I've received help from a different source but he has so little time to spend with me and talks so quickly I can never get my photos moved. There is always one step that he forgot to tell me which screws the whole process up. Please help. My iPhone is really an iPhone 5c not 5s. I don't know if it makes a difference. I need to transfer them to Windows Vista operating system. Thank you to anyone who can help.