Learn Spanish (Latin America): Tú colocas el ratón ergonómico de manera que no te duela la mano. - You place the ergonomic mouse so that your hand does not hurt.

De manera que can introduce a purpose ("so that") or a consequence ("with the result that"). When it expresses an intended goal—like wanting to prevent your hand from hurting in the future—it requires the subjunctive (duela). You would use the indicative (duele) only if you were stating an established fact or completed result, such as describing a habit: "You always place the mouse in a way that your hand doesn't hurt."

Does the meaning change if I say de modo que instead of de manera que?

Not at all! De modo que and de manera que are completely interchangeable here. Both mean "so that" or "in such a way that," and both follow the exact same rules for using the subjunctive or the indicative.

Why does the sentence say te duela la mano instead of duela tu mano?

Verbs like doler (to hurt) work similarly to gustar. Literally, this phrase translates to "the hand does not hurt to you." The indirect object pronoun te shows who is experiencing the pain. Because te already makes it obvious whose hand it is, Spanish grammar requires the definite article (la) instead of a possessive word (tu) when referring to body parts.

Why does the verb doler change to duela with an "ue"?