In the sidebar, click "Administrative documents".

Open the dossier the piece has to be attached to.

A document produced outside OptimCE — a signed form, a letter from the grid operator — is declared here first, then receives its file.

Pick the matching form and give it a title your colleagues will recognise.

The upload icon lets you attach your own file instead of having OptimCE generate one.

Drop the file in the dedicated area, or click to pick it from your computer.

Every upload creates one more permanent version. A file already stored is never replaced: it is kept, and the new one becomes the current version.

The document now has a downloadable version, exactly as if it had been generated.

Open the versions to confirm the file was stored, with its original name and size.

The uploaded file shows up as version 1. Unlike a generated version it keeps no data snapshot: an arbitrary file says nothing about who it concerns.