In CURSE FORGE OR OTHER LAUNCHER,

Duplicate ATM10 version 7.1 into a new profile and call it anything such as "ATM Extended" Most of 
you should already have this version installed as it was the version for the previous server. Then in the new profile, 
click the 3 dots in curse forge or navigate to the instance folder for your launcher and copy all the mods from The 
file you have installed here and paste them into the existing "mods" folder folder. Any option should work but the SAFEST option
is to "replace all"

Once this is done allocate 1 more gig if possible and start her up.