user75102: Sorry, if I am wrong or silly!
It is understood that:
a) Satoshi Nakamoto sent the first transaction to developer Hal Finney on January 12, 2009, the genesis block contains 1,073 transactions and he got 50BTC as block reward, which is non spendable by design.
b) Coins are mined during block publishing.
c) A coinbase transaction must be 100 blocks deep before you can spend its outputs
d) Coins don't merge
e) For each transaction, sender should have group of input coins, whose sum should be greater than equal to sum of transaction amount and transaction fee.
What is the total amount of all those transactions and how they got BTCs for the initial transactions?

user13866: 
What is the total amount of all those transactions

You can see Bitcoin's genesis block here:
https://en.bitcoin.it/wiki/Genesis_block
You can easily examine early blocks by using the block height in any blockchain explorer. For example here 

how they got BTCs for the initial transactions?

Mined blocks can be empty (contain no transactions other than the "coinbase" mining reward). I guess this can be the case when the mempool is empty or when all the pending transactions therein have unattractive fees.

user4906: The genesis block is block 0:
block 0
-the reward went to the address 1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa.
The first regular transaction (from Nakamoto to Finney) is in block #170
txhash=f4184fc596403b9d638783cf57adfe4c75c605f6356fbc91338530e9831e9e16
-sent from 
12cbQLTFMXRnSzktFkuoG3eHoMeFtpTu3S to 1Q2TWHE3GMdB6BZKafqwxXtWAWgFt5Jvm3 with the change being deposited back to the sending address. These coins were over 100 confirms.
The 1073 transactions you are talking about was probably correct at the time of writing, but they are talking about the number of transactions sending coins to the address in the genesis block over the life of bitcoin.
-There have been 1,508 transactions (as of right now) which sent coins to the address in the genesis block, so now that address holds 66.91839465 BTC, 50 of which were from the genesis transaction. That means there have been 16.91839465 BTC sent to it. (1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa)

75102: <p>Sorry, if I am wrong or silly!</p>

<p>It is understood that:</p>

<p>a) Satoshi Nakamoto sent the first transaction to developer Hal Finney on January 12, 2009, the genesis block contains 1,073 transactions and he got 50BTC as block reward, which is non spendable by design.</p>

<p>b) Coins are mined during block publishing.</p>

<p>c) A coinbase transaction must be 100 blocks deep before you can spend its outputs</p>

<p>d) Coins don't merge</p>

<p>e) For each transaction, sender should have group of input coins, whose sum should be greater than equal to sum of transaction amount and transaction fee.</p>

<p>What is the total amount of all those transactions and how they got BTCs for the initial transactions?</p>
 13866: <blockquote>
  <p><strong>What is the total amount of all those transactions</strong></p>
</blockquote>

<p>You can see Bitcoin's genesis block here:</p>

<p><a href="https://en.bitcoin.it/wiki/Genesis_block" rel="nofollow noreferrer">https://en.bitcoin.it/wiki/Genesis_block</a></p>

<p>You can easily examine early blocks by using the block height in any <a href="https://www.google.com/search?q=blockchain+explorer" rel="nofollow noreferrer">blockchain explorer</a>. For example <a href="https://www.blockchain.com/btc/block-height/1" rel="nofollow noreferrer">here</a> </p>

<blockquote>
  <p><strong>how they got BTCs for the initial transactions?</strong></p>
</blockquote>

<p>Mined blocks can be <a href="https://bitcoin.stackexchange.com/q/61919/13866">empty</a> (contain no transactions other than the "coinbase" mining reward). I guess this can be the case when the mempool is empty or when all the pending transactions therein have unattractive fees.</p>
 4906: <p><strong>The genesis block is block 0:</strong>
<a href="https://www.blockchain.com/btc/block/000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f" rel="nofollow noreferrer">block 0</a></p>

<p>-the reward went to the address 1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa.</p>

<p><strong>The first regular <em>transaction</em></strong> (from Nakamoto to Finney) is in <a href="https://www.blockchain.com/btc/block-index/15019" rel="nofollow noreferrer">block #170</a></p>

<p><a href="https://www.blockchain.com/btc/tx/f4184fc596403b9d638783cf57adfe4c75c605f6356fbc91338530e9831e9e16" rel="nofollow noreferrer">txhash=f4184fc596403b9d638783cf57adfe4c75c605f6356fbc91338530e9831e9e16</a></p>

<p>-sent from 
12cbQLTFMXRnSzktFkuoG3eHoMeFtpTu3S to 1Q2TWHE3GMdB6BZKafqwxXtWAWgFt5Jvm3 with the change being deposited back to the sending address. These coins were over 100 confirms.</p>

<p><strong>The 1073 transactions you are talking</strong> about was probably correct at the time of writing, but they are talking about the number of transactions sending coins to the address in the genesis block over the life of bitcoin.</p>

<p>-There have been 1,508 transactions (as of right now) which sent coins to the address in the genesis block, so now that address holds 66.91839465 BTC, 50 of which were from the genesis transaction. That means there have been 16.91839465 BTC sent to it. (<a href="https://www.blockchain.com/btc/address/1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa" rel="nofollow noreferrer">1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa</a>)</p>
