Counting in japanese can be quite difficult. I've lived here for almost 10 years and I still make mistakes in this language.
If you don't know exactly how to count a specific thing, you can say 一つ、二つ、三つ、四つ(hitotsu, futatsu, mitsu, yotsu, and so on..), or add 個 (KO) after the number (一個、二個、三個, ikko, niko, sanko...).
For minutes, you must add 分 (pun, bun, fun) after the number.
一分、二分、三分 (ippun, nihun, sanbun) and so on.
I have 3 questtions = 私は質問三つあります(わたし は しつもん みつ あります)
I have 5 minutes = 私は五分あります(わたし は ごふん あります)
I only have 1 pencil = 私は鉛筆一個しか持ってません(わたし は えんぴつ いっこ しか もってません)
Hope this was useful.
Good studies!