"Stop Limit" can be used in three ways for buying a stock,
3 Regular order
If you are using either BO or CO - "stop limit" for buying a stock, you can place stop loss at the same time in same order window.
In case you are using Regular Stop Limit type, in that case you need to wait till your order gets executed, thereafter you can use regular order type for placing stop loss either by using Trigger sell + Limit price or Trigger sale + Market price
for better understanding pl go through this video