I want to connect generator [2kva] for my house ,please can you explain it with using diagram

If you review this,

Gentran Corporation: Generator Transfer switches for home & business

You can find whatever your looking for for products and wiring diagrams to suit your situation.

You can also jig up your own transfer switch for less than $100 if you go get a sub-panel box and (2) two phase circuit breakers (240V) sized to protect the wires, in my case I have a 30A on my 5KVA generator line and 100A on the power company lines. You make a bracket to connect the two breakers in the sub-panel mechanically (you have to remove the long rivets that binds the two individual phases together and replace them with a screw or heavy copper wire through the bracket edges) so when one is on, the other is off after placing them in horizontally opposite in the top load breaker positions. By powering all the circuits in the house with generator power, you will have to be conservative, but will have power to the entire house, which I find more convient because I already have 2 sub-panels at other locations in the house with circuits that I need to power when the power company does not come through. I have to find a place to put the picture I have...

Modifying electrical components that are UL Listed is not recommended, as suggested by the previous advice, and will violate the UL listing.

In the event there is an insurance claim, the fire inspector will find the modified part and will report the finding to an insurance carrier.

By the way, the 240 volt system in a home is called single phase, not two phase.