How does one recall all the dreams he had last night?

You can't start remembering all of your dreams right away, but after a few days you can get pretty close to all of them if you make a dream journal. Just place a tablet right next to your bed, and a pen. When you wake up from a dream, even if it's in the middle of the night, QUICKLY write down everything you remember. Even if you have to use quick notes and half sentences, like you did in school, when taking notes, write it all down.
Make sure this becomes a habit, and MAKE SURE you don't poo poo the idea because you are half asleep. Don't roll back over!
After a few days, you'll see the number of dreams in your dream journal, per night, start to get higher and higher.
On a good night I can wake up with five to seven dreams written down in my notebook. It doesn't just help you remember the dreams you have written down. It help your "dream recall" for all dreams, simply because you are practicing that part of your mind.

begin by increasing your vitamin B during the day, as it helps with dream RECALL the next day

Besides keeping a dream journal, you can also ask your spiritual guides to help you remember your dreams better upon waking.

Dreams are often guidance from the non-physical (spiritual) dimensions; so it will be useful for you to do so, and your guides will be happy to help all they can.

a pen and tablet will help. but you need to remember long enough to write your dreams down. dreams fall in the realm of psychology, so you can use psychology to help. before you go to sleep (as close to the last thing before sleeping you can manage) promise yourself ten times that you will remember your dreams tonight. and when you wake up, train yourself to have your dreams be your first thought. you should aim to remember your dreams before opening your eyes.

1.) Keep A dream journal, and record all the dreams that you can remember.
2.) Do not set alarms, because they will disrupt your REM cycle.
3.) When first waking up, DONT sit up right away, the chemicals released from dreaming, and sleeping will disappear making it harder for you to remember, if you stay laying down, and thinking about the dream you are more likely to remember it for a while.