connect to console

# prepare ssh keys first

# login droplet
ssh root@ip.of.the.droplet

# to copy a file from B to A while logged into B
scp /path/to/file username@a:/path/to/destination

# to copy a file from B to A while logged into A
scp username@b:/path/to/file /path/to/destination

perpare ssh key

• How To Use SSH Keys with DigitalOcean Droplets | DigitalOcean

achieve

• Save a snapshot and delete droplet
• restore droplet by the snapshot

Update Server’s Kernel

• How To Update a DigitalOcean Server’s Kernel | DigitalOcean