How now I can run the master node, if necessary sum of 300 000 XAB? And one more question, I see that the master node 79.119.43.54 sometimes off-line. What will happen to the chain, if it is a long time to be off-line?
You need to have 300.000 XAB in your wallet as a collateral. If you have that amount you just have to click Create Local and thats all.
If a masternode goes off-line nothing happens, since the PoS block aren't generated by Masternodes. These are getting only rewards from PoS.