Zanna, what Douglas said plus just use the pointer finger for now (forget about the others). Place the big part of the thumb in the center of the neck at the back, lay the pointer finger right across all the strings and pinch the neck hard between finger & thumb. Get the index finger just behind the first fret. Roll the pointer finger backwards a slight bit (roll back towards the head of the guitar). Pluck each string slowly and make sure it rings true. Re-position the pointer finger very slightly until each note rings.

This will create the necessary hand strength and get you used to making the elusive barre. Practice this drill every day for maybe 5 minutes until you can do it easily, each note rings true every time (plupp = fail!) and your hand doesn't ache anymore.

Then progress to the useful F chord (actually it's the E chord shape but barred up one fret).