If you are using Shopify online store 2.0 you need to follow the process
After completion of your slider, Click on “Publish to store”
Select the “Theme version 2.0” tab and click on “Publish” button.
From the left sidebar, add go to “Add section”
here, you will see the silder you have created
Now click on the slider to add it on the page and click on “Save” on the top right corner.
If you want to publish the slider on other page, you need to use drop down menu and select the page. Then follow the steps from 4 to 6.