Much better than the one you buy unless you can get it from a good bakery. Not that difficult, you just need to take your time.
For 2 puff pastries. You can freeze one, if you only need one.
190 g butter
250 g flour
5 g salt
120 ml water
If you have some doubt, watch the video at the bottom of the page. It is the one I have followed the first time I made it.
Take the butter out of the fridge.
Put the flour in a bowl. Ding a hole in the middle. Pour the salt and 3/4 of the water. Mix with your hands to dissolve the salt. Add the rest of the water and mix until getting an homogenous bowl. With a knife incise it with a cross shape to relax the dough.
Wrap it into a cling film. Put it in the fridge for 30 minutes. Put the rolling pin in the fridge.
Press the butter to have a square 2 cm think.
Roll out the dough to have the shape of cross and a flat hill in the middle.
Put the butter in the hill. Fold down each branch of the cross on the butter to shape a small square. Seal the corner. Level the top by hitting with the rolling pin. Roll out the dough on a floured surface to shape a long rectangle. Move the rolling up and down (never left to right).
Fold down the upper third onto the middle one then fold down the lower third onto the two other.
Quarter turn anti clock wise and roll it out again to shape a long rectangle. Again only move the rolling up and down.
Fold down in three with the same method as before. Mark the dough with 2 finger prints to remember you've done 2 foldings. Wrap in cling film and put in the fridge for 30 minutes. Put the rolling pin in the fridge too.
Repeat the rolling out and folding 2 times with 30 minutes rest in the fridge in between. After the last one divide the dough in two pieces. You can use one straight away and put the other one in a freezer to use another time.
A few tips
Stay in a cool room (19C)
Put the rolling pin in the fridge to keep it cool so you don't mix the butter with the dough
Roll out gently at each step