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: Select Keyword targeting
Step 9: Add kw that you want to target. You can read further how to conduct kw research by clicking here, and more about different match types here. Good practice is to have all match types of one kw in one ad group. In this way you will avoid duplicating keywords for same product thus much easier ad optimization. In this section you need to assign bids to each keyword. Another good practice is to have different bids for different math types. For the exact you should have highest bids, for phrase match type 10% - 20% lower and broad match type 30%-40% lower than exact match type.
Step 10: This step is optional. You can add your brand kw as a negative if you have separate "Brand" campaign which will make it easier to measure your brand impact.
Step 11: To start the campaign click on the "Launch campaign" button.