Loganberry is a hybrid with a blackberry, so like a blackberry it roots at the tips of the branches. So arch a long branch so that it touches the ground at its tip, and peg it in place. Once it’s rooted well and is growing from the tip, you can sever the branch.
You may find you already have several rooted!
To keep them in order - erect a rough framework or trellis about 1.7m high. Plant your loganberry in the middle and tie a couple of branches in each direction, forming an arch or even a circle. These will produce side branches and fruit.
During the summer, gather up any new branches and tie them in a loose bundle vertically up the centre. Just let them flop once they’re above the height of the frame.
When fruiting has finished, cut out at the base all the branches that have fruited. Cut loose the bundle of vertical stems, choose the strongest to tie in for fruit, and cut out all the weak ones at the base.
This works for all the blackberries and blackberry hybrids (boysenberry, tayberry, sunberry etc)