Step 1: Go to Appearance >> Customize
Step 2: Find Sidebars
You can change General Setting, Single Sidebar Layouts, Dual Sidebar Layouts here and choose Sidebar for default Pages, Search Page, Front Latest Posts Page, Blog Posts, Blog Archive, Case Study Posts, Case Study Archive, Single Product, Product Archive.
Step 1: After creating a page, come to Page Options
Step 2: Find Sidebar
Choose Sidebar and position you want to use and Hit Publish.