I have made a field in hr.timesheet.sheet view, with that I can select all projects like this:

class hr_timesheet_sheet(osv.osv):
    _inherit = "hr_timesheet_sheet.sheet"
    _columns = {
        'project_field': fields.many2one('project.project', 'name'),
    }

I put that in the timesheet like this:

        <record id="hr_timesheet_sheet_tree_test_fields" model="ir.ui.view">
            <field name="name">hr.test.fields.tree</field>
            <field name="model">hr_timesheet_sheet.sheet</field>
            <field name="inherit_id" ref="hr_timesheet_sheet.hr_timesheet_sheet_form"/>
            <field name="arch" type="xml">
                <xpath expr="//sheet/group/group" position="inside">
                    <field name="project_field" string="Project"/>
                </xpath>
            </field>
        </record>

How Can I make now 2 buttons that show me exactly the tasks and the documents of the project that I selected in the timesheet view?

I need to take the project.project function and then use them in the hr_timesheet_sheet view with new buttons...

This 2 buttons with the same function per project in this view: