I just made a piece of bun and it tasted better than I hoped for, so I'm
very encouraged

The bread (or bun) I made consists of flour, sugar, salt, water, olive oil.

I'm not looking for receipes, but rather theories. For example:

how do I make the bread fluffier? more yeast?
how long to wait for the yeast to rise?
do I need to put oil/lard/butter in the bread, what if I don't?
do I have to knead the dough a long time, what if I don't?

If there is an FAQ that covers the above and more, please point me to it.
Thanks.