How to Reach the Shrine
This shrine is easy to reach from the top of Lanayru Tower. Just look downward from the north side of the tower, then float down to the shrine.
About the Soh Kofi Shrine
This shrine is one of many "test of strength" shrines that you can find across the land. These shrines contain a Guardian Scout of varying difficulty levels. It might shoot beams at you as you approach, so raise your shield after the Guardian appears. If you have good timing, you can press A to use your shield to bounce the beam back at it, damaging it. Then go up to it and try to hit it. If its shield is raised, you can knock it back with a club or other heavy weapon. Otherwise, try to jump out of the way of its attacks at just the right moment so you can do a Flurry Rush.
If it jumps back and puts its arms straight out at its sides, run behind a column (but don't stand too close to the column) because the Guardian will spin until it hits either you or some other obstacle. If it hits the column, it will be damaged and stunned for a while, so you can run up and attack many times.
If it jumps back and lowers its head, its about to spin around shooting a weak laser, so you can either try to rush up to it and hit it repeately to try to stop this attack, or you can run to a safe distance while it spins the laser. The laser creates an updraft, so you can jump and use the paraglider to float up, allowing you to shoot an arrow in slow motion at the Guardian.
Another attack it can do is charge up powerful blasts. It will jump back, turn its eye blue, and raise its head before it does this. You can try to quickly rush up and attack it repeatedly in the hope of stopping it before it can charge up the attack. Or you can keep your distance and raise your shield and try to parry the attack, but you will be badly hurt if you miss. Otherwise, try to run circles around the Guardian so the blasts just miss you. These blasts will break through columns, so don't try to hide behind them.
When the Guardian is defeated, take its weapons/shields (which are useful against other Guardians) and get any ancient loot it drops, then go open the treasure chest to get a Knight's Bow, and talk to Soh Kofi to get a Shrine Orb.