i repair / rebuilt the database and no auto increment field was displayed. i also changed the values in the database to auto increment and still nothing
Can you verify the table contents in mysql to see if the fields are really empty?
select * from tasks_cstm;
If they are not empty, then I suspect that the referenced field in the list view does not correspond to the custom field that you created. You may try to
go into studio
remove the field from the list view
close studio
reopen studio
add the field to the list view
The zip file you downloaded contains more than just the module and is not the installable module itself.
When you extract it contains a parent folder dtg-autoincrement-master
To be able to install the module, you can create create the installable module by creating zip file of the files/dirs: SugarModules, LICENSE.TXT, manifest.php, README.TXT
making sure to omit the parent folder.