Essential regular things to do I am a beginner cyclist.So ,I want to know which things I have to do regularly.And what will be the time interval ?

Example :Pump,tuning etc.
Check your tire pressure regularly.  Different tires (tubes, actually) have different "leak down" rates, but at a very minimum check once a week, and probably every 3 days (or before every ride).
Clean/lube your chain.  Depends a lot on riding conditions, but in "average" conditions you should clean/lube every 200 miles or so.  More often in wet, sloppy conditions or in extremely dusty conditions.
Inspect your wheels.  Hold the end of the bike up and spin the wheel.  Check for any wobble (watch right next to the brake blocks for rim brakes) and check that there are no serious bulges in the tires.
Check your chain for stretch.  Get an inexpensive chain stretch gauge and check after you clean the chain.  Replace the chain when it's too far stretched (about every 2000 miles).
Check your sprockets for wear when you replace the chain.  How to do this is a bit involved for a short answer.
Check your brake blocks for wear maybe every 500 miles.  The blocks should be mating nicely with the rim and not worn to the point that the metal holder is close to scraping the rim.


There are others I'm not thinking of at the moment.  And this question is likely a dupe and there are other threads with more info.