How to use google slides:
1. Access to ´Google sites`
2. Click on ´Create - New - Google slides (presentaciones)`
3. Go to File / Page setup / Standard 4:3
4. Go to File / Publish to web / Start slideshow (ok) + Restart (ok)
5. Publish
6. Copy link
7. Embed - Ir al google site - Edit webpage
8. Insert / More gadgets / Slideshowmaker
9. Insert the ´Link to presentation` / save
10. Quitar checks y establecer el tamaño de la presentación en 100/300