The next step is wrapping your line around the spool and to secure it by trying an overhand knot. The type of line you are using, decides the type of knot that you should have in order to spool a baitcaster. An arbor knot is your best choice if you are thinking of spooling a baitcaster with monofilament backing.
A simple arbor knot does the best job and is widely used for attachment. This knot can be easily tied and with more pressure, it further tightens its grip. This is a very strong knot that makes sure that the mono and the braid are in perfect alignment with each other.