What is the Lower Toolbar? This is where you will have majority of the additional functions when you post.
Functions such as "Smilies", "Attachments", "Settings" and also the "Poll" function.
You may not be able to use all the functions, all the time. This will depend on if you are making a post or a thread. The level of your subscription (if indeed you are a subscribing member) will also determine what you can/cannot do.
Where is it, how do you get to it?
When you go create a new thread/post, you are presented with the following text box and along the bottom, you have the four clickable sections: your Lower Toolbar.
If you click on Smilies, a little dropdown opens and you can then choose whichever emoticon fits the mood of your post. Within that dropdown, you will notice 3 sub sections, Default Category, Square and Lairy. Click on them, see what happens
If you still want more help on the Smilies section, plenty more information here.
The Attachments section, I will not go over as it has already been covered here in a good amount of detail.
The Settings, when you click on this, you will have some more options to play with. Sometimes depending on what are you posting, or what sort of thread you are creating, it may be appropriate to enable/disable certain options. This is where you are able to customise your post/thread a little further.
The Poll? Well you might want the opinion of the masses in a poll format, which will give you easy-to-read results as opposed to trying to follow every single post. And it can be fun too, sometimes.
If you wish you get rid of a dropdown, simply click on the corresponding button again and the dropdown disappears. For example, if you have all the smilies displaying, and find it annoying, click on the Smilies button and they will then hide.
Hope that has made it easier. Happy posting.