There are actually four bleeder valves: one on the expansion tank, one on the crossover pipe (top front of motor), one on passenger side closer to the back of the engine, and one on a tube coming off the top of the radiator on the drivers side near the expansion tank.
Since you replaced the t-stat, make sure that temp sensor is reconnected properly. If it’s not moving on the dash, there’s something going on with the temp sensor that needs to be addressed.
As for the bleed procedure, I’ve only done it once. Several people swear by the vacuum filler method, but I didn’t have a vacuum filler - but that might help solve your problem. The method I used is below (had my son help me). In the steps of the procedure when the engine is running, it’s essential to keep an eye on the engine temp - shut it down if you start overheating and let it cool off - and make sure the coolant tank doesn’t go empty (you’ll get air back into the system). Since you’ve already refilled the system at least partly, maybe you don’t need to do this whole procedure, but I’ll list it out anyway.
1. Loosen expansion tank and put something underneath it (or wedge it) to keep it raised about 1.5 inches from it’s original position. You just need the lip to be higher than the highest bleed point. Doesn’t take too much.
2. Loosen three bleed points - on the expansion tank, on the crossover, and back of the engine towards the firewall.
3. Fill the expansion tank to the rim and keep filing until it starts to escape the crossover bleeder - close that bleeder.
4. Keep filing until it starts to escape the bleeder towards the firewall - close that bleeder.
5. Close the tank bleeder.
6. Open the fourth bleeder near the radiator, not far from the expansion tank.
7. Start and run the engine and keep adding coolant until coolant starts to run from the radiator bleeder. Close it off.
8. Turn off the engine for a couple minutes. Set the heater on high and start the motor. Hold the engine speed at about 2000 RPM until the coolant level in the tank drops. Have someone ready to add coolant if necessary - need to keep it near the cold fill at least.
9. After the coolant level drops, raise the RPM to 3500 until hot air is emitted from the face vents. Shouldn’t take too long. Keep an eye on coolant expansion tank and keep level in the cold fill range.
10. Put back the expansion tank.
11. Keep topping off the coolant level after driving until it becomes stable.