Let me get this straight.
This is the first time you ever changed your own strings, and you decided to change to BEAD.

Good luck with that.
If you are not familiar with setting up your own bass, my suggestion would be to bring it to a guitar tech at your local music store to do the set up for you. It's going to take some tweaking to get it to be playable. Truss rod adjustments, string height, intonation, and then adjust the height of the p/ups.
You could also do a search here to learn how to set up your own bass if you want to experiment for yourself. You may even find someone who has done the same thing and had the same question. Google would also be a good place to find articles on how to do a proper set up. Bass player Magazine has had some good articles as well.
IMO, the cheap Yamaha five string basses don't have a very good B string, so don't expect much from converting a four string, but you should be able to get it to be playable.