[QUESTION] How all this started?

[superpanos2]

Well I know the basic about bitcoins.
It started in 2009, but how?

1. when you create a wallet, you have 0 balance, so you need to buy bitcoins
2. miners find the blocks and the get rewarded some btc for the blocks (used to be 50, now 25) + transaction fees.

BUT how was there any transactions(see 1.) to  write in the blockchain and let the miners generate coins?

Was there and bonus for creating a wallet?

[Eli0t]

transactions make up a small part of the block reward so after mining the first block your balance would be 50 (in this case)

[marcovaldo]

Blocks are generated every 10 min (average).
You do not need to include transactions in the block in order to get the rewards. So, at the beginning, you can mine btc without including any transactions.

[Gabi]

This, you don't need transactions to make a block. To be accurate, there is always at least 1 transaction in the block: the one for the bitcoins just generated.

Almost all blocks back in 2009/2010 had 0 transactions (except the one for generated coin of course)

[DeathAndTaxes]

Was there and bonus for creating a wallet?

Initially the "miner" was the wallet.  You installed the wallet and it mined blocks in the background and your wallet balance grew as you solved blocks.  All blocks must have 1 transaction that is the coinbase transaction but there is no input for that transaction as the miner is rewarded new coins "minted from nothing".   A block doesn't need to contain any additional transactions so mining doesn't stop when there are no pending transactions, it just means the block will consist of only the coinbase.

As an example here is an early block:
https://blockchain.info/block/0000000027c2488e2510d1acf4369787784fa20ee084c258b58d9fbd43802b5e

Notice there is only one transaction, the coinbase tx in which the miner received 50 BTC for solving the block and no other transactions involving existing coins.

[superpanos2]

nice thanks 

[dooglus]

BUT how was there any transactions(see 1.) to  write in the blockchain and let the miners generate coins?

You can take a look at the early blocks:

http://blockexplorer.com/b/1
http://blockexplorer.com/b/2
http://blockexplorer.com/b/3

You'll see they don't contain any transactions apart from the block reward itself.

[elor70]

satoshi nakamoto started it all blame him!

[mprep]

Well' everything started with the big bang. After millions of years of evolution bitcoin was born... and that's pretty much enough for you to know.