Create groups
Groups are useful if you have multiple ads that need to into one spot. The group then alternates between those adverts. A group is also a good way to set up ad locations and easily manage those spots from the dashboard. Even if there is only one ad in the group. A group can hold one or many adverts and they can work in different modes.
Group modes
Groups serve multiple purposes and can operate in different modes depending on your needs.

A group can work in one of three modes:
- Default - Show one advert at a time and requires a page refresh for a new ad to load.
- Dynamic - Show a different advert every few seconds without reloading the page.
- Block - Show a grid of multiple adverts.
A group can operate in one mode at a time and can have as much adverts as you need. Depending on your settings these will rotate and be picked at random. This is a semi-random process. You can influence the randomness with Advert settings such as weight, geo targeting and schedules.
Dynamic and Block mode
Block size
This option is for block mode and determines the grid you're making. Think of it as a spreadsheet. Rows go horizontal, columns vertical.
This way you can make an actual grid of 2 by 2 ads. Or a single row of ads across a page. Or stack a few ads in the sidebar. Just to name a few possibilities.
Advert size
This option can be used for both Dynamic and Block mode and sets some size rules for the adverts. The size in pixels for the advert is determined this way and directly influences a grid of adverts in Block mode.
For Dynamic mode it serves mostly as a height limit so the rotation looks good.
Automatic refresh
Used for Dynamic mode and sets the amount of seconds for each advert to show. Think of this as a automated slideshow for your adverts.
Post Injection
With post injection you can place the group on certain locations on pages and blog posts.
With AdRotate Pro this also works for WooCommerce products and bbPress forums.
Post injection adds adverts inside the content without using code, widgets or shortcodes.
More information on Post Injection can be found in the Post Injection manual.
Wrapper code
You'll need HTML and/or CSS knowledge to effectively use this option.
This is an advanced feature where you can add HTML code specific to the group, around each advert. While you can manipulate the group output to add a border with CSS, for example to add a border or extra space. Sometimes a bit more customization is required by adding your own HTML code.
Block mode
This is a special option for groups that shows multiple adverts at the same time in a grid-like fashion.
Using the options in the group you can make advanced setups like for example; a single file column of 10 adverts in your sidebar or a 2x2 square of ads.

For example: If you want a 2x2 block of 125x125 ads but each ad has a margin of 10px. In your theme that translates to 125px + 10px = 135px by 135px. In the 2x2 grid the total block size will be 270x270px.
AdRotate calculates all that for you, based on your settings, but your theme is ignorant for these numbers and won't budge. So make sure things fit in the area you want the group to show up in.
Configuring a bunch of 300x300 ads in a 2x2 grid will never fit inside a sidebar for example.