Starting to get students used or coding can start with something very simple. One way I use to get student used to putting algorithms together and get used to using iterations (loops) is to get them to draw three squares of difference colours on a 20 X 20 grid (such as the one shown on the right here. Students can then use commands to write a set of instructions to draw the squares:

Students will probably write an algorithm that has a lot of individual instructions, so here is where the idea of loops / repeats can be introduced to see if the code can be simplified. The next exercise is to look at the external angles of the shapes that are going to be drawn, I use a sheet for the students to follow and give them the teaser question of "How many sides does a circle have and what would be its angle?" Once students have discussed and corrected their answers, the can move onto using Scratch to try and draw their shapes. I use a Google Document (one for each student) and I give them the (long) instructions to draw a triangle (middle picture below) and most students will be able to use a repeat to then simplify the code (shown below on the right hand side) 
Now it's time to hand things over to the students for them to draw all the shapes (and screenshot the evidence that the shape has been drawn and the code).
As an extension activity, I get students to try a nested loop that rotates the shape around to draw some nice graphical patterns. An example in Scratch can be viewed here. The full resources for this activity are available here. I have usually used a quick Youtube video to step through the parts of the lesson and you can try flipping your classroom by getting students to view it as homework before coming into class to try the different challenges (my Youtube video is below) 