The only way to practically node without a keyboard is the ubiquitous "cut-and-paste" method.

Find something that you have written previously (like poetry, prose, even noding your homework), cut-and-paste it to the writeup window on E2, then find an open square-bracket, copy and paste it to the left of your intended link, then find and copy a close square-bracket and paste it to the right of your intended link.

Be aware that cut-and-paste nodes of copyrighted or superfluous information are very frowned upon by the noders at large. It is suggested that you avoid them at all costs.

So, it's possible to node relatively more effectively than the single-character method, but perhaps you should just spend the $7 on a new keyboard. If you're near a university, you can sometimes get beat-up keyboards for free, or even look into second-hand shops.