Odoo Erp Action button in one to many field sending the object to a custom view of an existent model

Briefing: Hi, I’m using Odoo 14 Enterprise Version and I’m having trouble with the sales module. In the sales order model, in the default one to many fields i want to add a link or button and redirect the page to a custom view of the sales order line model with the object of the selected line where i should be able to view filtered the list to the selected data. And from there i want to select multiple rows so i can work the data of the selected rows in the PDF Requirements: 1.-In the default sales order form view we have a one to many field for the sales order lines and we need to create a action button like the one in the example: 2.-The action button redirect to the sale order lines custom form view (like the one below) in order to add or edit other fields not included in the one to many previous field.
3.-In the default sales order form view we have added a tab and we would like this tab to have the sale order lines items and a action button grouped by Subcontratista field so we will have only distinct names in the list and also we need to have a sequence of the distinct Subcontratistas (example if we have 2 distinct Subcontratistas we need to have the first row with the number 1 and the second with the number 2). 4.-After clicking in the action button of the previous one to many field we would like to redirect to the sale order form view to be in the scope of the selected Subcontratista with all his linked items (also the sequence from the previous step), so even if we create a sales order line will be linked to the same subcontratista.
5. Then we would like to make a custom PDF with the object that contains all the items of the model.