I learned how to curl on this site what worked for me was reference points. First find the button and work out in your own way.  use higher power also and to estimate from there with memory.  Worked for me but not sure if its the best way to learn good luck

Sweeping works believe it or not just left click the mouse after you release the rock and move your mouse side to side.  You only need to sweep if your light or if you need to add it to the angle of your shot.

Well, the point is to have your colored stone closer to the middle of the center of the rings than your opponent when the end is over.  You can use guards {stones that aren't in the rings} to block your opponent from removing your stones, it's a large part of a curling game. 

The power bar will move from blue to white and back to blue. When it is just about to leave the white and go into the second blue area, right at that mark is the power you need to draw to the button or t-line. 

For take outs, the more power you use, the more inaccurate your aim will be. So use enough weight to make your shot and that's it. Also, the less weight you use, the more likely your rock will stay in play. 

Draws can be made around guards to hide a rock and are very important. It's a lot harder to take rocks out that are hidden behind guards, so getting rocks hidden is very useful. 

My advice is to figure out draw weight first because you can hide rocks and make it tough on your opponents and you can always throw them a little heavy and bump rocks if you have to.

The less weight you use, the more the rocks will curl so you need to "take more ice". That means aim your broom further away from where you want your rock to come to a rest. If a rock is curling too much, sweep it. Move the mouse button and move the mouse back and forth quickly. This will keep the rock from slowing down as much and will stop it from curling so much. So the rock will go further and get around guards without hitting them. 

Also, when throwing the rock, use a little less power than you need. That way if you throw it a little heavy, you're still ok. 

A rock in play is better than a rock tat is out of play, no matter where it is.

On the Start Game page there is a Practice Mode where you can play against yourself and really practice your power and aim.