Evil Eyes are fundamental to Friede's whole gameplan, so you need to get used to them. Button pressed after the motion determines which eye is summoned: P summons an eye with a pink aura right in front of Friede, K summons an eye with a blue aura further away, at ground height, S summons an eye with a green aura at the same distance as K, but above head level, and HS summons an eye with a red aura further away, at the same height as P. If you need help associating button and eye, look at the colors of the auras and the placement of each eye: they match the buttons on a PlayStation controller.
If you press a direction right after summoning an eye, you can alter the direction it's facing: the default is forward, but you can have it face backwards, upwards or downwards.
If an eye is already summoned, pressing its button will fire a laser out of it. You can fire 3 lasers consecutively from any eyes you have set. If you press the button of a not-yet-summoned eye, it will summon that eye and interrupt your lasers string. Lasers are composed of a thicker, short-range hitbox, and a thinner hitbox that reaches far away.
When hit by a laser, the opponent will be launched in the direction the eye is facing, so you can shoot the opponent away from you with a forward-facing eye, pull them towards you with an eye that faces towards you, launch them in the air with an eye that faces upwards or knock them down with an eye that faces downwards. On block, eyes facing forward or downwards will push the opponent away, and eyes facing backwards or upwards will pull them towards you.
Below Friede's healthbar are 4 bat symbols, with colors matching the auras of the eyes. When you summon an eye, the corresponding bat symbol will turn black to indicate that the eye is out. By using O or 22O, all summoned eyes can be recalled, generating a small hitbox as they disappear, which can be useful for combos, neutral or pressure. You can summon eyes again right away afterwards.
When you place an eye and decide its direction, it's important to take into consideration which eye you're placing, the matchup you're playing and what you plan to do as the match goes on. Even if you accidentally place the wrong eye, or give it the wrong direction, don't immediately consider it a failure and recall them, as you might be sacrificing other eyes as well, and even that "wrong" one may turn out to be useful later.
As far as the P eye is concerned, it comes out right in front of Friede and any direction can come in handy. Facing it forward is good to keep opponents away if it's the kind of character that wants to get close to you, but it won't reach the full screen. Facing it backwards is mostly planning for the future, so it's recommended if you already have eyes to handle what's in front of you. Pointing it upwards can be a useful tool to deal with jumps. Downwards only comes in handy if you're in the air while placing it