I don't know how to start learning Mandarin.
Pinyin is very important.Because it's the base of pronunciation.Then you need the language environment to practice more and more.
Yes.Pinyin is basic.
To understand the pronunciation of characters you need a pinyin. pinyin has own rules, so you need to pay attention to it.
With all do respect to Tanya, Pinying is not the way to go. It will do you a good job of confusion.
Start with learning the characters themselves. trust me, they aren't that difficult. It will also help you remembering the tones.
Give it a go and you'll see
The first month focus on pinyin, learn words