hi
you need to warm the emulsion before being able to use it.
that means squeeze a little out of the bottle or with a plastic spoon
scoop a little out of the tub it is in, and put it in a small container
that is clean. put that small container in warm water so the water bath
( water "jacket" ) warms and melts the emulsion in the small container it will
liquify so you can use a brush or rod and coat your paper or glass or metal or plastic or rock or wood or ....
painting / brushing it on paper is easy and painless.
on other materials it can be a little more effort ( you have to make sure everything is extremely clean )
i never use the hardener that comes wtih the products, but i use a hardener in my fixer, it works well.
there is information on using liquid emulsion on a handful of websites on the web
i kind gave you the "highlights"
you might poke around the rockland colloid website and read their instructions
https://rockaloid.com/instructions-msds-links
they won't be any different for a different brand emulsion
you might also look at
http://www.alternativephotography.com/the-liquid-emulsion-process/
and
http://thelightfarm.com too ...
have fun !
john