Let us count.

I by mistake send transaction without fee and he now is unconfirmed.
It is possible to increase fee for this transaction or cancel it?
I see long time ago somebody was posting how to increase fee using blokcain.info but I don't remember how and don't find with search.

This is hash of trans action https://blockchain.info/tx/3bf353132e0a5490cd4c3cab7a84211adcbb5eadd09612dcf5139397500c7b7a

[this guide]

I look for guide how to setup Ledger Nano with Electrum.
I find this guide in Ledger website but it is too old and all pictures don't work also hi is for Linux and I search for Windows - can somebody help me.

What is different between Sweep and Import private key in Electrum.
Sorry my English is bad - I am from Bulgaria

How to dump all private keys which consist bitcoins.

I know how to dump single private key but when I make transaction change can coming back to one hidden address

Please somebody to add me to Telegram Bitcoin group as @filchef