Is it possible to train a toddler to keep the toys automatically after they have played with it ? Any tips ?

Yes it is :) Set by example, and make it fun too! In fact, the younger you start, the more likely they'd follow through. Firstly, be sure that your child is done playing with the toy - if your child takes it out again or makes a mess with it, that means he/she is not done playing! Once you know that your child is tired of the toy, you can start with a cleanup song - you can make up your own, or there are songs that you can reference to on YouTube and sing it to your child. Keep them with your child and encourage him/her to do so too, you can also make it fun by turning it into a game :)