Oh crikey, where to start....
Well, to move your character you can use the W, A, S and D keys aswell as using the arrow keys to look around. Assuming you found yourself in the Lonely Cave for the first time, there are portals you can go through to get to different maps. There's very little point in staying in the Lonely Cave because, as you may have already guessed, it is pretty lonely. Go for a run around in the maps, talk to some people, maybe make new friends, join a roleplay if that's what you're into, and just generally explore the different functions or play around with the character creator.
Given that it's a weekday, there will probably be fewer users online at this time because most of them are likely to be at school, work or college. But it tends to get a bit busier in the afternoons and evenings and at weekends.