It's a little bit more straightforward to add a player on the ROBLOX Player. At the top of the home screen, you'll see "Friends" and then a circle, that has an icon of two players, saying Add Friends.

Before finding out how to call people on Roblox using Roblox Connect, it’s worth pointing out that, at least right now, players can only do so if their account is voice-enabled (either via phone ...