Reposting edited question, non Muslim attending funeral

My friend, mentor, second only to my husband has sadly passed. I'm planning to attend the services this weekend and I want to be respectful. I (middle age F) plan to wear dress pants, shirt, and light sweater to be modest. Where do I find a head scarf? How do I wear it? What do I look for in shopping? Where to shop? (I'm in upstate NY).

Any tips and helpful hints are appreciated.