Algorithmic Thinking is the third of the three key techniques needed for Computational Thinking ( finding the steps you need to take to find the best solution to a complex problem)
Algorithmic Thinking is a logical way of getting from the problem to the solution. It is working out the steps you need to take and the order you need to take those steps in. If those steps follow an algorithm then they can be reused to solve the problem again in the future and (and this is important) similar problems. A good example is putting a list of numbers in order.
Step 1: You compare the first 2 numbers (a and b) putting the smallest one (a) first
Step 2: Now compare the next 2 numbers (c and d)
Step 3: Repeat step 2 (moving to next pair until you get to the end). This is logicial, there are simple steps and it can
Step 4: Go back to start of list and start again
Step 5: Keep doing step 4 (looping) until there have been chnages to the order of the list of numbers
This set of steps is simple, it is easily repeated and It will also work regardless of what the numbers are.
You could write a similar algorithm for making tea (just to continue the example). When building an algorithm solve each of the small subtasks (from decomposition) then put all those solutions together.
Algorithms are built from three basic logic stuctures - Sequencing,Selection and Iteration (loops). Follow the links to find out more about these.