Welcome to Steemit, @Mshindi.

Here are a few helpful posts I've discovered since I joined a few days ago. You could start by reading the FAQ.

https://steemit.com/steemit-guides/@pfunk/a-user-s-guide-to-the-different-steem-keys-or-passwords

https://steemit.com/steemit/@gaman/new-to-steem-series-1-my-number-1-rule-secure-your-owner-key-failure-to-adhere-to-this-rule-results-in-massive-loss

https://steemit.com/steem/@hawaryatef/the-differences-between-steem-steem-dollars-and-steem-power

https://steemit.com/minnowsupport/@shinyforest/a-minnow-s-guide-to-steemit

https://steemit.com/steemit-101/@dan-atstarlite/steemit-101-everything-you-need-to-know-about-your-steem-wallet

https://steemit.com/minnowsupport/@rodeo670/steemit-tutorials-how-to-set-your-profile-picture-cover-image-display-name-about-location-and-website

https://steemit.com/steem/@taskmaster4450/pissing-away-hard-earned-steem-power-why

Hope they help.