I guess you're talking about site workflows? If it is already published than you do it the same as in on premise - go to site contents and the "workflows".

If you want to edit a site workflow then you must again go to site contents and then click the "Nintex Workflow" app.

About scheduling - as I answered to your second question already - there in no such feature OOTB in O365 Nintex.

Regards,

Tomasz

Thanks Tomasz.

Actually I have  list workflow which I want to start manually. This workflow will send notification based on a date field but don't see option to start it manually neither any option for scheduling.

As I wrote - no scheduling OOTB in O365.

For list workflows to start a PUBLISHED workflow manually, go to item menu --> more --> workflow and then click the name of your workflow.

Again - no possibility to put direct link to start a workflow in a item's context menu as it is possible in on premise. The above is the only way

Regards,

Tomasz