Cement render is like playing with play dough or molding clay! You take a special mix of sand, cement powder, and water and mix it together until it's like a big ball of dough. Then, you take that dough and spread it all over the outside of a brick wall or building - just like spreading frosting on a cake!
Once the cement mixture is spread evenly over the wall, it dries and becomes very hard, just like when you leave your play dough out for a long time and it gets hard. This hard layer of cement helps protect the wall or building from bad weather like rain or wind.
Some people like to add different colors or patterns to the cement before they spread it on the wall. That way, the wall can look fancy or unique!
And that's what cement render is - a strong and protective layer of cement that can make a building look pretty too!