Networking question

I'm going to create a small network, but 2 other people I know wants to have access to it from their laptops when they are out of town.

What kind of software and hardware would I need to be able to arrange this if they use modems?

I'm sorry if this question sounds a bit stupid, but I'm a self-learner (learning as I go), so I'm not quite sure how I should approach this without making any slip-ups.

Any help at all would be very appriciated.