Applied at Dollar Tree for Unknown

I received an email from Dollar Tree inviting me to set up an interview. They provided a contact number and asked me to share my availability. Now I'm debating whether to call or text the person. Additionally, they mentioned open interviews happening soon. I'm unsure if I should coordinate my schedule with the contact or just show up during the open interview times without making a phone call. I'm leaning towards calling since they specifically gave me a number to reach out to.