There is a couple of PDF documents, the first describes quick tasks for lemon, that guides the vendors in the way to use the Point of Sale. The second is a shortcut keys for both applications, lemon and squeeze, created to have in hand while the vendors is begining with the Point of Sale.
There is a wiki on sourceforge. It has an installation guide, including one for ubuntu, and a small user guide.
You can watch some videos or screencasts showing live demo of lemonPOS. You can see the videos here. Comming soon, please be patient...
There is also a mailing list to ask any doubt you may have. Follow the link and subscribe to it and write to the list asking for the help you need. Its low traffic and in english, we prefer this way to make a searchable knowledge base, so anyone can find the discussed themes in the list in the future.
Need some special feature, now?
If you need special features or adaptation to your business, we can work for you. We accept donations for small works that benefit you and the community, but also we can talk about a special work for you. Contact us.