Navigate to the Web Auto Scale Rules page and take a look at the Auto Scale rule. Click on the blue edit rule button.

On the upper left side of the rule you can see the upper and lower bound for dynos. These bounds set the max/min dynos this rule will permit. For a relatively low traffic application with some periods of high traffic its sensible to set the lowerbound to 1 and the upperbound to 2.

On the lower left side of the rule you can see the Upscale and Downscale Configuration. On the Upscale configuration, the first field is the request queue threshold. It determines when more dynos are needed to meet the traffic needs of your application. Once the threshold is exceeded, Dynoscale will upscale your application by an increment set in the next field. Finally, to avoid frequent scale ups, the last field delays incremental scaleups with a buffer time.

On the Downscale configuration, the first field is the request queue threshold. It determines when to reduce the dynos needed to meet the traffics needs of your application. Once the request queue drops below the threshold, Dynoscale will downscale your application by an increment set in the next field. Finally, to avoid frequent scaling, the last field delays incremental scale downs with a buffer time.

Once you are happy with a rule, click on the green save button in the upper right side of the rule. Alternatively, if you don't want to save changes, click on the black cancel button.

An application must have a default rule. It dictates how the application should scale when other rules are not active. To create another rule, click on the "Create Rule" button at the top of the Auto Scale Rule page. You will notice that unlike the default rule, this rule has a dropdown for day of week and fields for start/end times. These fields determine when a rule is active. When rules overlap in time, the topmost rule is selected first.

To shift the priority of a rule, you can use the black arrow buttons on the right side of any non-default rule.

Once you are happy with the rules, click on the toggle on the upper right side of the page. Red indicates that your rules are off and greens your rules are active.

Most of the Worker Rule fields are the same as the Web Rule fields. One exception is the Queues field, it specifes which queues are applicable for a rule. To ensure a cost effective usage of autoscaling dynos, make sure to only include queues which have time sensitive execution.