2 year old apple pruning

i planted 3 apple trees and over the next few days would like to

inconvenience you all for some pruning advice. 

i BELIEVE the tree pictured is a Honey Apple (im in japan) IE Malus pumila Rosaceae, grown on a "Maruba kaido" root stock. It came in a "pollinator set" along with another tree (which I hope to figure out which variety tomorrow and post next). it was planted as a one year old tree in the autumn of 2024. 

 I have a great book by orin martin that has a lot of information and I've watched videos by him and several others, but I don't want to get this wrong so I'm reaching out to you all before I have a go. 

i am wondering if this particular tree may be good as an open center instead of a central leader as it seems to already be taking that form. I don't want these trees to get massive but with about 5 m of space between them I guess they could get to 2.5-3 meters? I prefer not to have to use a ladder for harvesting, but at the same time, if it means more fruit, then I'm not entirely against it:). 

i did not do any summer pruning as i was hesitant to make any missteps and im worried the branches have grown too long.  i know i should be establish structure but need advice as to what cuts to make and where. 

help!