The D5.3 Open Call Package and Communication Toolkit Deliverable report documents the selection and support process for third-party beneficiaries under the SUNDANSE project. The SUNDANSE Open Call #1 – The Danube Call aims to provide a maximum of a €100,000 lump sum grant and a 9-month programme to at least three selected projects. Eligible applicants are Local or Regional Authorities (or a consortium of up to two) from associated regions. The objective is to accelerate the replication and scale-up of SUNDANSE sediment management solutions, focusing on core thematic areas like flow/sediment monitoring, quality assessment, or awareness raising.