Thanks, but i dont really understand

Maybe i will try to follow the guide with apache insted.
I have read that apache is much more ram hungry then nginx, but maybe i can live with that. I have about 500-1000/users that visit sites on the server.
I will most have e-stores at this vps, and i want the site too be fast as possbile. (The stores are in wordpress and Opencart.)
Should i try more with nginx or should i go for apache2?
Thanks!