class TargetSetup(models.Model):
    _name = 'target.line'
    _inherit = ['mail.thread', 'mail.activity.mixin']
    _rec_name = 'date'

    date = fields.Datetime(string="Date",default=datetime.today())
    which_line = fields.Many2one('line.information',string="Line No")
    production_target = fields.Integer(string="Production Target", required=True)
    estimated_hour = fields.Float(string="Estimated Hour", required=True)


class LineDetails(models.Model):
    _name = 'line.details'
    _inherit = ['mail.thread', 'mail.activity.mixin']

    date_select = fields.Many2one('target.line', string="Select Date")
    target = fields.Integer(related='date_select.production_target',string="Production Target", required=False, )
    estimated_time = fields.Float(related='date_select.estimated_hour',string="Estimated Hour")
    which_line = fields.Many2one(related='date_select.which_line', string="Line")

I want when I select date and which_line filed then show all related field .

How to do it can you help me please ?