I am not sure if this is the best way to handle the filament change w/o an AMS … you would imagine it’s not too much to ask for the software to automatically pause (and even notify with a message to the App, like it does when a print finishes) for a manual change. In any event, I learned this the hard way trying to print the chamber light, which was preconfigured from Bambu to use black and white filaments.
First, slice the model. Then, on the right-hand side of the screen when viewing the sliced model, there is a slider that you can slide down and watch the layers of the print disappear. Once you get down to the layer immediately preceding the filament change, you right-click on the + of the slider and say “Add Pause” then you re-slice and send to the printer. (I imagine if you have multiple changes, you can add multiple pauses, but I have not tested).
During the print, the printer will pause. Navigate to “Unload” and complete an unload operation. Then remove the current roll and install the next. Warm up the hot end as you normally would to load filament and purge a significant amount into the waste chute to ensure the prior color is completely flushed out. When complete, set nozzle to required temp for your filament. Navigate to the Home screen, and press “Play” to resume the print. Somewhere along the line, the nozzle temp may revert to 0°C, so again, make sure the correct temperature is set for your filament.
Hope this helps.