To remove the trigger, start by pressing out the trigger pin with a punch.
With the trigger pin removed the trigger can now be pulled out.
Reassemble by moving the trigger back into position making sure to keep the trigger spring in it's proper locations and replacing the trigger pin.
These are the trigger parts you removed.
This is how those parts go together.
The trigger bar pin can be removed from the trigger by pulling it out.
Reassembly is done in reverse order.