Welcome! Look for any interesting posts on the Firehose and jump in. (It's easier to grok the layout if you start out using it in a regular computer browser.) Start to follow people whose posts you find interesting, so there will develop a My friends column of things you're most interested in seeing. It's not about how many followers you have or how many people like or boost -- everyone sees every post, by default.
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But also feel free to mute people you just aren't as interested in. You can't read every post. It's not an insult, it's just "using the tools."