Below is a link to official information on obtaining a Tourist License. Click the link and then click Q&A's in English
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You said Villamartin but some areas that are often referred to as Villamartin actually come under San Miguel (El Galan, El presidente etc) and obtaining the Certificate of Compatibility needed for the application for the License is handled differently at the two Town Halls.
You are welcome to message me with any specific questions about holiday letting. The Tourist License became compulsory in 2015 yet, sadly, many estate agents still fail to mention the requirement. As you have just purchased recently you should be able to use both the EPC and habitation certificate that were done for the sale of the property in your application.