Custom Form Options

I am trying to set up an upload form but not getting very far.
Using [photosmash_form] on http://kewstudio.org/classes-workshops-tuition/virtual-exhibition/

I found this message:
Check that ‘Use Custom Forms’ is turned on in PhotoSmash Settings/Advanced

BUt I went to PhotoSmash Settings/Advanced and couldn’t find ‘Use Custom Forms’ anywhere. It has Use Custom Fields but not Forms.

I am a bit baffled and happy to buy ImagePress except that I am not sure it will be much easier to use!

I am a designer and would happily work with you to improve the interface! I know you are working hard to make what could be a great plugin.

Thanks again
Sarah

https://wordpress.org/plugins/photosmash-galleries/