When flashing I use a 3.3V power supply so I never switch.
I personally like the tutorial https://www.allaboutcircuits.com/projects/flashing-the-ESP-01-firmware-to-SDK-v2.0.0-is-easier-now/
That's what I used.
I use a USB-TTL adapter and I built that circuit because I have the parts.
That programmer you bought should work, but they are new.
You may want to read http://www.arjunsk.com/iot/programming-esp8266-esp-01-using-esp8266-programmer-ch340g-chip-adapter/. The photos are too small.
Also read: Review & tips: generic USB ESP-01 programmer (ebay) - Everything ESP8266
.