meganL, If you've never before been the sort of person to call/write your representatives and/or the President, it might intimidate you to do so. Don't be intimidated. They're supposed to be working for you - they're your employees.
Resistbot is a tool that can be helpful for people who don't like making phone calls. You can do it a variety of ways, following the bot's prompts https://resist.bot/
If you want to contact the WH directly, they have some tips here: https://www.whitehouse.gov/get-involved/write-or-call/ #USpol