Step 1. Create a page named Blog (or whatever you like)
Step 2. Go to Settings > Reading and set Front page displays to A static page. Then set appropriate Posts Page to the page you created in previous step (Blog)
Step 3. Go to Appearance > Theme Options > Blog to configure your blog page.
Step 4. Go to Appearance > Widgets and drag widgets to Main Sidebar or Blog Sidebar if Blog Layout is set to Sidebar Left or Sidebar Right layout in previous step.
If there is any widget in Blog Sidebar, it will be used in stead of Main Sidebar