I would like to understand how to access the cloud and more specifically a small cloud to search / select a cloud service? are there any tools or platforms that can help?
This actually depends on a vast array of factors. From a user perspective, I think you should first identify your needs and define the budget you are going to invest in the chosen service which might be also free in some cases (Trial period or Basic subscription), but with limited functionalities and features. Basically, Cloud computing can be accessed via a web-based interface which contains an administration Panel that enables you to interact with the service platform you are subscribed to. The on-demand cloud platforms philosophy relies on a subscription-based pricing model which means you pay only for the service you pick up . The existing service cloud computing providers offer low-cost services for different business models. To dive deep into technical details we need to know which service you are interested in (SaaS, IaaS, PaaS, etc.) as well as your motivation and objective.
Sounds like you need a Cloud Computing Middleware. Please, check the following link to help you clarify your need :http://www.fujitsu.com/global/about/resources/publications/fstj/archives/vol47-3.html
Once you finish reading, please, ask us more technical questions to help you sort out your problem.