Enabling customizing for a Wordpress blog

One-hour call: I am looking for a web developer to show me how to enable customization to a blog. The blog is part of a bigger website, so the changes need to be applicable only to the blog link excluding the remaining of the website. Web developer is required to also recommend which plug-ins need to be acquired and how to add them in order for customization to be enabled. Right now the whole website is according to one theme, and we want the blog in another theme (which we already acquired). The web developer is required to give directions as we do the changes ourselves. The whole process will be a one-hour call with screen-sharing, payment through People Per Hour.