No you don't put detergent and fabric softener together as they will not work properly together.
You put the fabric softener in the washing machine during the rinse cycle or in the fabric softener dispenser separate from the detergent.
When using fabric softener in your washing machine the fabric softener is released by the washing machine during the final rinse cycle.
So put the fabric softener in the fabric softener dispenser of the washing machine if it has one.
If your washing machine doesn't have a detergent dispenser or a fabric softener dispenser and it's a top loading washing machine then put your detergent into the washing machine.
Then start the washing machine and let it run through the wash cycle and when the washing machine gets to the rinse cycle you then put the fabric softener into the washing machine.
Don't mix the fabric softener and detergent together as it will not allow the clothes to wash properly and will make it hard for the detergent to wash fully out of the clothes.