The file mask_holder v3.stl is the file just printed by itself in PETG or PLA.

if you however wanted to print the middle section in tpu you have to slice the other 3 files with cura seperately but with the x and y positions calibrated in a way that they would overlap with the complete file. Afterwards all the gcodes have to be placed in a folder(with the names of the stl files) and my python script downloadable at https://github.com/Magnesium117/Fuse3DPrints. The offsets for part 1 and 2 are 0.3 and between part 0 and 1 there is a filament change.

Your printer needs to be capable of M600 filament change