Pedro:
The films listed in the database are all available through the Church of Latter Day Saints and you can order them at any one of their family history centers located throughout the US and the world for a nominal fee of $5.50. Some films are on permanent loan to group members and those who are willing to do ad hoc lookups for other members have listed their names next to the corresponding films.
Many of the films have been indexed by the LDS and those that have will have a button labeled "IGI" for International Genealogical Index or "VRI" for Vital Records Index just after the description and date ranges. If you click on the button, it will take you to familysearch.org where the indexed information is available to search online free of charge.
I would suggest that you (and any other new member) donwload two very important documents that are available in the Files section of the site under Reference Materials:
1. Nuestros Ranchos User Guide
http://www.nuestrosranchos.org/node/14123
2. Guide to Mexican Church Records
http://www.nuestrosranchos.org/node/14701