Step 1: Login to your Amazon Advertising account
Step 2: Click on the "Create campaign" button
Step 3: Select Sponsored Products campaign type by clicking on the "Continue" button under the tile
Step 4:
Step 5: Select bidding strategy. Leave the default selected, you can change this setting later on after the campaigns is optimized.
Step 6: Create Ad group. Using consistent nomenclature here is also very important. Good rule of thumb is to add only one child ASIN per ad group, so the naming of the ad group should reflect that.
Example: "Child ASIN - color/size"
Step 7: Add products to advertise. As mentioned in the previous step you should add only one product per ad group especially in auto targeting campaigns.
Step 8: Set default bid. Amazon gives you an opportunity to set different bids by target groups. If you are setting campaign in a account for first time, it does not have any CPC history you can look at the suggested bid for clues what is the bid range in your category. For the close match you can use the suggested bid, but for the rest set the bids at least 20% - 30% lower than the close match.
Step 9: Adding negative kw targeting is optional. There are some cases where you should put negative kw preemptively. For example if you are selling vitamins you would like to add negative terms like "dog", "cat", "pets" so the campaigns does not pickup wasteful traffic. In other case you might put your brand name as a negative term.
Step 10: To start the campaign click on the "Launch campaign" button.