Hello Sroeurn Suon,
For the active_ids, You can create wizard models and form view and also creates the act_window for that wizard, From that you can used the active_ids which is selected records from tree.
For Example :
wizard.py :-
from odoo import models, fields, api
class WizardModel(models.TransientModel):
_name = 'wizard.model'
name = fields.Char ('Name')
@api.multi
def wizard_method(self):
self.ensure_one()
sale_order_ids = self.env['sale.order'].browse(self._context.get('active_ids'))
print "sale_order_ids ::::: ", sale_order_ids
wizard_view.xml :-
<record id="wizard_model_view" model="ir.ui.view">
<field name="name">wizard.model.form.view</field>
<field name="model">wizard.model</field>
<field name="arch" type="xml">
<form string="Wiard">
<group>
<group>
<field name="name" required="1"/>
</group>
<group/>
</group>
<footer>
<button name="wizard_method" string="Ok" type="object" class="oe_highlight"/>
or
<button string="Cancel" class="oe_link" special="cancel"/>
</footer>
</form>
</field>
</record>
<record id="action_wizard_model" model="ir.actions.act_window">
<field name="name">Wizard Model</field>
<field name="res_model">wizard.model</field>
<field name="view_type">form</field>
<field name="view_mode">form</field>
<field name="target">new</field>
</record>
<act_window id="multi_wizard_model" multi="True" name="Multi Wizard" res_model="wizard.model" src_model="sale.order" view_mode="form" target="new" view_type="form"/>
Here res_model : wizard.model name
src_model : For you create act_window
When you selected multiple sale.order from tree view, In action view You can see Menu which is Multi Wizard, so from that open wizard and when click on OK, You can use active_ids for selected sale.order
Hope it will works for you.
Thanks,