How I can add new folder on Appian "Default community" and then upload file on this folder?

Hi Gioachino,
You should try the following to upload to a newly created folder in process:
1. Create the folder using the Create Folder smart service. Save the folder name as a pv!.
2. Create a script task node and then as an output call the tofolder() expression and pass in the pv!folderName. Save this to a pv! of type Folder.
Ex: tofolder(pv!folderName)
3. Pass in this new Folder pv! to the file upload field, as the file upload field requires a Folder object type and passing in only the folder name or calling the tofolder() expression in the field itself will not allow the field to access the folder in the DKC correctly.

Hi Gioachino,
You should try the following to upload to a newly created folder in process:
1. Create the folder using the Create Folder smart service. Save the folder name as a pv!.
2. Create a script task node and then as an output call the tofolder() expression and pass in the pv!folderName. Save this to a pv! of type Folder.
Ex: tofolder(pv!folderName)
3. Pass in this new Folder pv! to the file upload field, as the file upload field requires a Folder object type and passing in only the folder name or calling the tofolder() expression in the field itself will not allow the field to access the folder in the DKC correctly.