All holes have a FRONT depending on the speed and break. On a straight putt, the front of the hole is truly the front of the hole (the part of the hole closest to you). However, on a right to left put which is downhill, the front of the hole will now be on the right side of the cup.
Think of the hole as a clock face. Sometimes, depending on SPEED and BREAK, the front of the hole will be 3 or 4 or 7 or 8 or 6. That is what I mean by finding the front of the hole.
Remember SPEED ALWAYS DICTATES THE LINE. NOT VICE-VERSA