Ways of learning
There are many different ways you can learn sign language. This includes online but it is always good if you practice with a friend or someone who can check your doing it right.
1. Find a class somewhere in your local area, type in “sign language courses near xxx” or if you live in the UK you can use the signature website to find a local course (http://www.signature.org.uk/british-sign-language).
2. You could also look on the internet for sign language dictionaries. They will have videos telling you how to sign the sign and similar signs you can use. Put the country you live in first as there are lots of different sign languages and you want to be able to learn the one from your own country. For example if you live in an English speaking country if your to search for sign language, American Sign Language will most likely be the top result.
3. Watch signed songs on YouTube, you will pick up a few words and they are really interesting to watch.
4. Finally, talk with deaf people who can sign, even if you can only use the most basic signs you will be able to have a conversation. They can also correct you and show you other signs to help you build your vocabulary.
Sign Languages do have grammar rules, that could be different from your spoken language, so look them up, or this is where it would be best to have an actual teacher who can help you.
Have fun signing, practicing with friends really helps. Tomorrow will be books/films with deaf characters.