Finger Position Exercise
Now we’ll do a simple exercise. Play the E string on the 1st fret producing an F with finger , 2nd fret F# with finger , 3rd fret G with finger , 4th fret G# with finger . After you have played each note you can take your finger off before you play the next note, you don’t have to have all fingers on the fretboard all the time. But make sure you keep each finger on the fret long enough for the note to sustain.
With your right hand or picking hand use your thumb or plectrum to strike the string as you make notes. Once you can do this on the E string move to the A. Then the D and so on, using the 1st 2nd 3rd and 4th frets, when you are really confident and you get to the highest point on the top E (4th fret little finger) go backwards using all the same rules but in reverse.
Playing the guitar may feel a little uncomfortable; make sure you move your hands into different positions, the smallest change in posture may make it much easier. Move your arms and your whole body to make it as comfortable as you can while you practice. Try to do 20 minutes a day at this point, half on the music theory naming notes and other half on the finger position exercise.