Step 1: Click on the Spark button on the left side just below the stream button of your profile home page.
Step 2: On clicking this Spark button it will guide you to the new page as shown in the figure given below. Just go to the text box and enter the thing’s which you are interested in.
Step 3: Once you have entered your interest click on the search button on the right of this text box. On clicking this it will show the latest updates based on the keywords you have searched for. Click on the Add Interest tab just below the text box to add this interest in your Spark. Once this is done, you will notice the new entry on your interest in your Google+ Spark of your profile homepage.
Above in the figure you c an see the final result once you have added your interest in Google+ Spark. Now after adding up your interest in Google+ Spark, whenever you require to have an update about you interested activities you need only have to click this and all the updates will be displayed.
Since Google has been the master of Search Engines, it has tried to keep this flavor in its latest Social Networking site Google+. But how much this new feature of Spark will attract new users depends upon upon their responses. The search result which Google+ provide while using Spark is more or less similar to the search results produced by Google Search Engine. This Spark does not seemed to be different from Google Search Engine, but one thing is good with Spark feature in Google+ is that one can have the list of their favorite interests at one place.