[?]HowTo share files among Debian PCs with WiFi

[bkpsusmitaa]

Along with multiple laptops we also have a few Android smartphones. File transfer from Android smartphone to PC is fairly simple, if either of the systems uses the same WiFi network. File Manager is set up to transfer files using unique network address, port, username and password to have the files/folders transferred. Simply enter the network address with port and with username and password to open a path between the two and have the files transferred.

For the other way round, we could use the PC to transfer via networking via bluetooth to tthe Smartphone

Example in the following Drive folder with images.
http://bit.do/shareFiles

Unfortunately for me, I don't know how to do the same in PC without using the BT network, but the WiFi network common to the either of them.
The Terminal-based ssh-client and ssh-server is in itself very scary.

Reading about vsftpd currently. gsconnect appears not be available. Presently, studying one page: How to Share Files Between Linux Systems | Unixmen, by Giuseppe Molica - January 18, 2017

I create a folder called share under my home/user/ and place a text file.

Last mile observations and questions:
The matter has been handled in a very complicated way. Why should user be bothered on nitty gritty of opening port 21 of wifi internet device? Android doesn't require that the port 21 of the wifi device be opened up. It makes do with what it within its limits. May be, all system resources better be virtualised to be delivered in a certain standardised manner.

How do I serve this file on pcmanfm one my HP laptop? How do I access this file as a client from my Lenovo?

Any other possibilities that my more experienced, intelligent and knowledgeable Forum Posters could share please, using the simple pcmanfm file manager?