I've been trying to gain access to my bitcoins, currently residing in an Electrum wallet on Windows 10, from my Android phone after installing the Electrum app.
Entering the 12 seed words doesn't enable the 'Next' button.
Most likely you typed something wrong or chose the wrong word (whenever it gives some options, when you type halfway), make sure to double check for errors or missing words.
Could someone let me know how this is supposed to be done?
Same process as you did. Standard wallet > I already have a seed
Is it possible to share across phone and desktop in some way??
Yes, I just did the whole thing again (in case there's an issue) and everything worked perfectly.