TextType, and nothing else is switched on
No camera and no microphone are involved at any point in text mode. It is the same random 1-on-1 format as the other two — one stranger at a time, skip whenever — just in writing. If your instinct about video is "not yet", this is where to start.
VoiceThe one people forget exists
Voice gets you tone, timing and hesitation — most of what text is missing — while nobody sees anybody. It is also the least awkward mode to leave, because there is no face registering it when you go. If video feels like too much and text feels too slow, try this before you give up on the site.
VideoFastest read, highest bar
Video tells you in seconds whether a conversation is worth having. It asks more of you in return: camera access before it can start, and somewhere you do not mind being seen. On a phone you can switch to the rear camera during a call if you would rather show the room than your face — that is a phone thing, laptops usually have only the one camera.