Hello @Rewive , Welcome to the Forum.
you can use
scp command to transfer files from your host computer.
‘vsftpd’ may be easier command application than scp on ssh. How about ‘samba’? offers GUI for file transfer and sharing. ‘minidlna’ is convenient for media file sharing in network. Those are on service in my VIM1S. SD Card is enough for me as storage and cable LAN is better for stable network. If you may not mind another physical unit, USB attached HDD or SDD is capable for data storage. It is recommended to format with exfat(msdos) started at 4096 cylinder. I use this kind of drive for eMMC backup. Those setup procedures are shown here and there in internet including youtube.
SSH is not very convenient, networking would be much easier. The VIM1 with an external SSD USB drive attached will handle a LAMP stack very well and you can also use samba if you need to use a Windows box.
You would normally SSH into the server to up load your files, filezilla on your host / client will do a good job for that