A lot of people need help and don't like to ask. The following is based on the experience of science writers who have travelled a tiny way up the learning curve. Most of the material mentioned here is freeware, although there is often a more advanced commercial version that you can buy if you like the freebie. Most links here take you off to the WWW site where you will find the software. Where the author encourages such practices, one or two point to local copies.
All suggestions welcome.