I have successfully completed the following turorial:

https://www.youtube.com/watch?v=JHSLN6wcL7o.

But I have a problem, when I start the process I have the requirement to upload several files (in the process start form I have a Documents control). When I launch the form from the central business this control is shown on the form but when I launch it from my application it is not shown (only the control of uploading a single document appears).

Nor does the Documents control appear if I launch the form content from the API endpoint.

With reference to my before mail/publication.
I have 25 variables type org.jbpm.document.Documents in my business process.
I execute, in the service folder, the "launch.bat clean install" command, and when compiling the kjar, the log shows this error:

[ERROR] / E: / 91 BUSINESS APPs / AuditAppCopo / AuditAppCopo-kjar / src / main / java / en / tecdesoft / stage.java: [31,34] package org.jbpm.document does not exist

When I start the form, the log shows:

WARN 2864 — [0.0-8090-exec-5] o.k.s.s.j.u.f.r.AbstractFormRenderer: Field type DocumentCollection is not supported, skipping it ...

From mvnrepository download the jar from org.jbpm.document, version 7.25.0, I add it to my kjar to trying solve the problem.
I execute the "launch" command.On kjar compilation there aren't errors but when launching the start-process form the log shows the same as before:

WARN 2864 — [0.0-8090-exec-5] o.k.s.s.j.u.f.r.AbstractFormRenderer: Field type DocumentCollection is not supported, skipping it ...

o.k.s.s.j.u.f.r.AbstractFormRenderer
This class is not able to handle type documents