How do I make the extra sounds on a Japanese Keyboard?

So I got some Hiragana stickers for my keyboard, i put them on, but then i realized something. The extra sounds weren't there. So what I'm asking is this; how do I switch from ほ　to　 ぽ? Not that exactly, but how do i get those extra sounds? I know I can use the romanji input method, but I honestly would love to know how to do without it