Especially with remote work, not sure how to organize.
Remote work didn't stop you working, did it? Why would it stop unions from working? There's on the ground work for sure, but it's mostly desk stuff, especially in IT.
The same way you organize anything. Start by talking to a couple trusted coworkers to form an organizing committee. All the members of the OC need to talk to coworkers, handle workplace drama, agitate for better conditions, educate people about unions, maintain systematic campaign tracking, and fight against the boss during their union busting campaign. When I worked remotely, it was as simple as sending a dm like this:
Hey, would you be able to talk over break? Some coworkers and I were discussing some issues and I wanted to hear your thoughts.
Form out of band relationships with coworkers you trust to get a base going then send an email to everyone from your department from an anonymous email address to solicit feedback and organize a vote.