the command to laod a file into remotes is /load -rs filename.ext
replace filename.ext with the actual filename like myscript.mrc
Also the mIRC help files are extensive and quite good
type /help topic
like /help /load
here is the help on /load:
/load <-a|-pscqnm|-ruvsN> <filename>
Loads the specified alias, popup, or script.
/load -a aliases.ini loads an aliases file
/load -ps status.ini loads a status window popup
/load -pc status.ini loads a channel popup
/load -pq status.ini loads a query popup
/load -pn status.ini loads a nickname list popup
/load -pm status.ini loads a menubar popup
/load -ru users.ini loads a users file
/load -rv vars.ini loads a variables file
/load -rs script.ini loads a scripts file
If you try to load a file that is already loaded, it's contents are updated and it's position in the alias/script processing order is maintained.
You can also use the /reload command with the same parameters to reload a file without triggering the on start/load events in the script being loaded.
If you specify the N with /load -rsN, this loads/reloads the script into the Nth position in the script list.
Note: You can only load one section at a time.