if you use Windows then :
1. close your wallet
2. open a file explorer and in the command bar, write %appdata%
3. go to the atmos folder and check if there is an atmos.conf file, if not, create one (text file)
4. for a list of nodes, I suggest you to go there :
https://chainz.cryptoid.info/atms/#!network and click on "node list"
5. copy all the addnodes in the file atmos.conf , save file. Restart your Atmos wallet. that's it.
if you use Apple then :
lol
I just done it. Thank you so much for your help!