As a part of Kodstuga, I participated in constructing a small introductory course to Arduino, mainly aimed at high school students. We’ve structured the booklet in such a way as to allow students to use the material on their own.
Additional: for those who are interested, I would recommend getting more sensors such as movement detector, termometer, etc.
In addition to more sensors, an interesting thing to try out is to get a NodeMCU instead. That’s because it has built in support for WiFi at a tenth of the cost if the same would be achieved using an Arduino and the WiFi shield (which is very expensive). It should be quite straight forward for those with an Arduino background, as we can use the same Arduino IDE together with a NodeMCU. A thing to keep in mind is that when you refer to PINs, you should use add a “D” in front of the pin value, eg. “D1”. More information can be found here.