Making a right turn or going strait at a 4 way automobile intersection is easy. You simply make the turn or go strait and take the lane, should that be necessary (only necessary in circumstances where an automobile might try to squeeze past or has might right hook the cyclist).
However, making a left turn is more complicated. There are two approches to making the turn, the right hook form and the normal left turn from the left turn lane.
First, the right hook is the longer and more inconvienient way of performing the turn. It involves the cylist making a right hand turn (or at least going to the far side of the intersection) and then waiting for the light to change to give green to the perpendicular direction and then proceeding straight.
Second, merging over the left turn lane and making a left turn automobile-style. If not done correctly or under the wrong circumstances, this can be quite dangerous (as with any manouver requiring crossing autombile lanes). Generally it is best to wait for all lanes to clear and then cross completely, especially when the traffic on the road is considerably faster (when there is not a sufficient gap, the right hook method should be employed). If the speed of traffic is only marginally faster or slower than the speed of the cyclist, then a multi-part merge is possible, where the cyclist can move over one lane at a time until he has arrived at the left turn lane, at which point he can proceed with motor traffic from the left turn lane. It is advisable to take the lane when making a left hand turn from the left turn lane. When there is more than one left turn lane, the rightmost of them should be taken.