It is possible to place related orders (for example take profit or stop loss orders) via the endpoint POST /trade/v2/orders/trade/v2/orders. The order object that you post to this endpoint holds a field called Orders. Inside this array you can place order objects for the related orders you wish to place. You can find examples of doing so in the resources below.
Related Orders are both validated when placed with Saxo, and when the main order has been filled. This is to avoid orders being placed on the wrong side of the market, but there are some scenarios to be familiar with.
With main orders that have a defined entry price different from the current market price such as a Stop Limit Order, some related orders may not be on the correct side of the market when placed, but will be once they the main order is filled. In this scenario, validation of these related orders uses the entry order price as the assumed market price, so you can properly apply a stop loss and take profit on the assumed entry point, with validation to ensure there no related order on the wrong side of the market.