In RHD countries, when in an uncontrolled 4 way intersection - in general you need to give way to vehicles on your right and also to any pedestrains on the section of the road that you are entering.
If you go straight at an uncontrolled 4 -way, then you must give way to vehicles on your right that are going straight ahead and vehicles on your right turning right. (don't forget the pedestrians as well)
If turning left give way to vehicles on your right going straight ahead and any pedestrians crossing the road that you are entering.
If turning right give way to vehicles on your right, oncoming vehicles that are going straight ahead, oncoming vehicles turning left and any pedestrians crossing the road that you are entering.
If both you and an oncoming vehicle are turning right, you can turn without giving way by passing in front of each other.
In the US (LHD) , you can usually turn right. At a 4 -way, the first to arrive is the first to go. When two vehicles arrive at a 4-way stop at the same time side-by-side, the vehicle furthest to the right has the right of way. So always yield to the right. Straight traffic takes the priority over turning. Right turn takes the right of way over left. Usually in the US the drivers keep eye contact and check and cautious over who starts to move.