You should be aware that certain instruments are transposing instruments. This means that they do not read in the same part of the staff as where they sound. For example, the guitar and bass transpose up one octave. This means that in order for them to play a middle C on the piano, one would need to write the note an octave higher on the staff. Pay attention to the clef an instrument reads in.
Guitar reads in the treble clef while bass reads in bass clef. Piano and harp use both clefs together. The woodwinds all read in treble clef, but they transpose up different intervals. For example, the alto and baritone sax transpose up a major 6th and 13th respectively, while the tenor sax transposes up a major 9th, the soprano sax up a 2nd, as does the clarinet and the trumpet.
Flute and violin are non-transposing and use the treble clef, while the trombone normally uses bass clef but can also read in treble clef. Viola reads in the alto clef unless the notes get high in the range; then they can switch to treble clef.
It can get a bit confusing when you are first learning, but it’s really not so difficult once you have an understanding of how the various instruments read, and what their ranges are. Most important at the outset is to know about your own instrument, whether or not it transposes, and what clef is normally used.
A correct pitch, when played at the wrong time, is a wrong note. Learning to count rhythms is, therefore, a very important aspect of learning to read music. To help you improve your rhythmic reading ability, there are exercises and tutorial programs one can find either online, using apps, or in books.
Drum books often have simple to complex rhythms written out that anyone could use to practice reading rhythms. There is also rhythmic solfege (naming the notes based on where they fall, e.g. “1 + 2 +”) to show where the down-beats and up-beats are. The word syncopation refers to notes that are off the beat, and written music is often highly syncopated, so learning to recognize and read these kinds of rhythms is important.
Just like when you learned to read English, you first had to learn the letters and rules of spelling before you could recognize words and phrases quickly. Learning to read music is no different.
You get the basics of the alphabet first, and how the letters sound. Then you put these letters and sounds into words, and later, sentences. Things that were difficult early on, later become easy. Anyone who makes up their mind to learn to read music can do so if they are willing to invest the time and practice.