With granular chlorine, dissolve the required amount in a bucket and add the dissolved chlorine around the parameter of the pool.
Using liquid chlorine, measure the amount required and slowly pour it around the parameter of the pool, never pour it straight into the skimmer.
With tablets, ensure you are using the correct type of tablet as the wrong type can actually cause damage.
It is important that you wear appropriate PPE when adding any form of chlorine to the pool.