It seems that right now there aren't very many Scientific Method jobs in Basque Country. Why not have a look at jobs in similar domains? Data Analysis or Financial Data Analysis jobs are overarching themes worth a look, as these are the main categories the job offers can be broken down to. If you're on familiar terms with domains like Data analysis, Research and Methodology, you're a shoo-in for jobs like this.
As it stands, there are neither internships nor junior positions available for Scientific Method. Sign up for Jobspotting to get notified as soon as some become available. There are many businesses right now displaying Scientific Method jobs on Jobspotting, but none of these are startups right now. If recruitment agencies aren't for you, you should be aware that 5 of 13 businesses recruiting in this area use them for most of their HR needs. Narrow down your job search by filtering them out of your feed if you want to. At the top of the page, you can see a map of offices in the region.