0 not difficult to do or to understand -- sencillo
It’s very simple to use.
1 not complicated -- simple, sencillo
a simple life
a simple dress (= without decoration)
2 used to describe the one important fact, truth, etc. -- sencillo, único
3 easy -- simple [ masculine-feminine, singular ]
4 not complicated -- simple [ masculine-feminine, singular ]
It’s a simple mechanism. Es un mecanismo simple.
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.
Podemos completarlo paso a paso, por muy largo que sea el camino, y no se puede completar, por corto que sea el camino, si ni siquiera marcas tu huella.