Question for Win Express (Yangon-Kyaik Hto-Kyaik Htee Yoe-Bee Lin-Tha Hton)

I would like to buy a direct bus ticket from Yangon to Kinpun on 9/9 and with return ticket on 11/9.
Same day want to go to Pathein. is there a connecting bus or train?
How much is it and where can I buy it in Yangon or online?