1. Upload images using Wordpress Image Uploader (please read Insert Images into Your Blog Post). Instead of clicking the Insert into Post Button, click gallery tab at the top of the image uploader window. If you don’t the Gallery tab, try to reload the image uploader window.
   

   Photo Gallery

2. On the Gallery tab, the order column determines the sequence in which the image is displayed. Type the number 1 if you want an image to display first. This step is optional.
   

   Order of Images

3. Set the options for your gallery:
   • Link Thumbnails To:  Select Image File or Attachment Page
   • Order Images By: You can select Menu order, Name, or Date/Time
   • Order: Show the images in ascending order or descending order.
   • Gallery columns: Select how many columns of images you would like to display in your gallery.
   

   Photo Gallery Settings

4. Click the Save All Changes button.
5. Click the Insert Gallery Button
6. Below is the sample Photo Gallery

Related posts:

1. How to Insert Images into Your Blog Post
2. 5 Image and Gallery Lightbox Solutions for WordPress
3. Refining Your Post With These Options