@pbhakat
Welcome to the #fediverse. Post whatever you like just as you would do in the old way. If you want to tag anyone to put an @ sign before the name. If you want to write about a topic add a hash (#) before the topic.

Follow and like people freely, #retoot as many posts as you like. Engage with people here.

All you basically need is one instance address to get started. You can follow anyone and post to your own instance that will on the fediverse network. In that sense it is similar to email or web page, this is the magic of #activitypub

There is more to fediverse than #mastodon. Your one address let's you access Instagram like image posts on an app named #pixelfed (tip: try searching it), YouTube like #peertube, Facebook like threaded discussion #friendica. You can push and pull from anywhere into your instance.

You can "dm' people but DMs are not like twitter, can be viewed by your instance owner. You cannot quote tweet, if you reply and write a note, that serves the purpose of retweet.

You can add media in #mastodon by selecting files after clicking the paperclip icon. Use 'cw' liberally, think of it as a header for your post or 'caurion'. When you post images always add an 'alt' so that people with limited vision can be included.

The keyword here is #kindness and #openness.

Look forward to read your posts.