You need to be a registered user. Once you are registered and logged in, click on the category you want to post under, then click on the sub-category. You will find at the top a pen icon. If you put the mouse over the icon it shows "new topic". Click on this to create a new post.
You would have to post them as a figure by uploading them as a file. If your questions or solution has equations or special mathematical characters upload the whole question or solution as a figure.
