Thought chains are chains of thoughts that are vibrationally related to one another. Every thought you think creates a thought chain containing additional thoughts that are related to the first thought in the chain. Thus, if you think about something you want, another related thought must then be attracted unto you due to thinking that thought.
If you think about being wealthy for instance, another thought of a similar nature must then be attracted unto you. If you think about a memory, you must then attract another thought that is related to the memory being recalled. This occurs with every thought too.
You can use thought chains to your advantage by creating desirable chains of thought. By thinking thoughts that attract desirable thoughts unto you, the attraction process can be enhanced as you think the most desirable thoughts possible to create the most desirable thought chains possible that will create the most desirable experiences possible.