I’ve no experience using hot air, but I do have a method for soldering parts like that with an iron that’s worked well for a few keyboards now.
- Melt a small blob of solder onto one pad
- Use tweezers to line up the part on the board
- Reheat the presoldered pad, use the tweezers to align the part and make sure it’s flat on the board
- Solder the remaining tabs
I’ll usually do step 1 for every board/part I’m assembling, then 2, etc. to avoid switching tasks a ton of times. Try one part a time until you get the process working for you.
It’s important to apply the step 1 blob quickly to avoid drying out the solder. I usually carry a small ball of solder on the tip of the iron and briefly touch the pads with it. Apply more solder as needed. Clean the iron if it starts drying out.