When I post a question, how can I choose which category to put it in?

After posting the question, go to Edit it and then select Change Category.  :)

a level 6 and you don't know the basics 

After the question posts in the keyword category, click edit and chose the category you want. On some mobiles, you may need to use desktop mode.

you can either put it in polls and surveys where the girls are or in politics where the gay rednecks are