so if i understand correctly. (correct me if i am wrong)
if my miners find a block i can decide which transaction to put in the block (up to 1mb transaction)?
for instance, i can do a transaction for 1 satoshi/B and if i find a block i can put that transaction inside it?
to find a block among all the pools its like almost impossible. am i right?
is there another way ? for small miners which dont have peta/exa hashing power?
If you're mining by yourself, the chance of you hitting a block is almost zero. If you're mining with a pool, you can contribute to the effort and you will be rewarded with your effort.
You got a sequence wrong, you specify which transaction to include first, then you try to find a block. The transaction hashes are in the merkle root, which is in the block header. Since you're hashing the block header to find a hash that meets the target, then you are effectively already selecting the transactions BEFORE you find the block.
why u have mention a node?
If you can select the transaction yourself, you would have to own a node to get all the transactions, blocks etc.
why? because i have to find a block first?
theoretically, if i find a block, how long can i hold it?
In theory, less than 10 minutes.
u mention the block reward,
the reward that u mention is 12.5 BTC? + selecting the transaction thats goes into block +getting the transaction fees? (again correct me if i am wrong)
The reward is: 12.5BTC(Block reward) + transaction fees of EVERY transaction that is included in your block.