Nocking by a push
It is possible to do the push nocking with arrow either on outer or inner side of the bow, while hand will always end in holding from the outside. I have not found any easy way to end with hand inside. Following is how to nock the arrow when it is on the outer side of the bow.
1) Hold the arrow by three fingers. Fingers must not reach from left side of arrow to its right side. One of the basic holding is whe the arrow is inserted in the groove in between straightened index and middle fingers, and thumb presses the arrow against this groove. Hold may be modified, but ends of finger must never reach the other side of arrow.
2) The arrow is put to bow from the outside, so that it leans against both the bow and the string; arrow shaft lies in the space between the bow and the thumb of the bow hand. This creates you a "rail" that you use when pushing the arrow forward. At the same time you correct rotation of arrow by rolling.
3) When the thumb of the string hand touches the string, you continue pushing on. The string will slip between the thumb and the arrow and will end in the space between the thumb and index finger, where is also the arrow. Push still on until the string reaches behind the nock of arrow.
4) Both the bowstring and the arrow are now in the narrow space between thumb and index finger. Now the hands starts to pull in the other direction. Narrow space between fingers guides the string and arrow nock to the same place, and the string will lock in the nock.
5) Fingers then slide on the bowstring to the required mediterranean hold from the outside, and the hand continues to drawing the bow.
Vaiants: If you want to end with the arrow on the inner side of the bow, change the move at point 2). The arrow shaft will be set only to the string and ńot to the bow. Before pushing forward you will set the arrowhead so that it points between the string and the bow. When pushing forward, the arrow will lean on the inner side of the bow and on your bow hand. As soon as the arrow is pushed forward enough, rest in on your front hand, and it will make you the required "rail".
It is natural to end in mediterranean hold from the outside, mediterranean hold below the arrow from the outside, or in slavic hold. Just the slavic hold is what seems most natural to me. If you want to end in the thumb draw, it is usually necessary to change your grip. I have found a way to end in thumb draw without changing the grip, but it does not suit me. Push-nocking is not suitable for any sort of string holding on the inside.
It is not neccessary to hold the arrow against both straightened index and middle fingers, because the index finger is enough - the arrow is pressed by a thumb against the side of index finger, which is bent down. It is less firm and not always useful (for example if you beat the arrow against the bow rather hard), but on the other side you use one less finger. Which is good if you hold more arrows by other fingers, and you cannot use them.
It seemed tyo me at the beginning that push nocking will be slower than pull, because it is not fluent (the hand goes first forward and then immediatelly backwards). Aftre some experiment the nocking by a push won a little bit. Push nocking is more reliable, which is the most important for me. Yet watching Lars Andersen, I must say tha pull nocking may also be trained so it is very reliable.