Can you explain this to someone with no much knowledge to scripts and devs ? (I have 2fa wallet)
Sadly, no... The simplified process as it stands requires you to be able to:
1. Disable the 2FA features of your 2FA wallet (restore -> 2FA wallet -> enter seed -> select "disable" -> DO NOT SET a wallet password)
2. Extract the 2 xprvs from your now "unencrypted" wallet file with a text editor
3. Get the "redeem scripts" for all the "3" addresses that hold coins
4. Use coinb.in to "decode" the redeem scripts and identify the "1" addresses that have been used to generate your "3" addresses
5. Use your extracted xprv's on
https://iancoleman.io/bip39/ to generate "1" addresses and matching private keys
6. Match generated "1" addresses from
https://iancoleman.io/bip39/ to "1" addresses from "redeem script" decode
7. Manually create a raw transaction in BTG Core wallet
8. Sign the raw transaction with private keys found at
https://iancoleman.io/bip39/9. Broadcast the signed transaction
Steps 1-6, aren't that difficult... and can be done relatively easily... a lot of point and click and copy/paste etc... Not super technical, they are just pretty time consuming.
Step 7 requires pretty indepth knowledge of how transactions are actually created and require some fairly low level Bitcoin fun... for reference:
http://www.soroushjp.com/2014/12/20/bitcoin-multisig-the-hard-way-understanding-raw-multisignature-bitcoin-transactions/Unfortunately, that article kind of glosses over the "spending" part of the process and "cheats" by using the wallet code to do it... We don't have that luxury here... as we're dealing with this at the private key level... and there aren't any BTG compatible tools

Step 8-9, aren't too difficult either...
Additionally, this process will also require that you install BTG Core wallet and download the entire BTG blockchain.
OR
You can wait until someone puts out a BTG compatible version of Electrum.