Unless you catch the puppy "in the act" or immediately after, there is no point in scolding it - they will have no clue as to why they're being scolded. Also, if they go inside, show them and then take them right outside. This will help it to understand and associate going to the bathroom with being outside.
Whatever commands you are trying to teach to you puppy, be sure to issue the command by saying the puppy's name followed by a 1-word command (Spot, sit, and not Spot, sit down). Dogs understand and remember one-word commands better and faster than more complex phrases. It also helps if you use a hand gesture while issuing the command.