<p>Unscrew the cover and take it off <a href="https://www.thoughtco.com/put-fishing-line-on-a-reel-1310741" data-component="link" data-source="inlineLink" data-type="internalLink" data-ordinal="1">the reel</a>. Some screw on, some have a notch and pin to hold them on.</p><p>Take all the <a href="https://www.thoughtco.com/mono-fluorocarbon-and-braided-lines-1310825" data-component="link" data-source="inlineLink" data-type="internalLink" data-ordinal="1">old line</a> off the reel. You can pull just enough line off so you can put enough new line on to make a long cast. Leave the old line for backing. This will save you money.</p><p>Run the line through the hole in the cover, coming from the rod end, and tie it to the spool of the reel. I find it helpful to run the line through the rod guides, from tip to handle, first. Use and Arbor knot and pull it tight. If you left old line as backing, tie the two lines together with two improved clinch knots or a nail knot.</p>Holding the line tight, put the cover back on the reel. Make sure the line is not pinched by the reel cover. Pull the line tight after putting the cover on.<p>Lay the <a href="http://www.scout.com/outdoors/wired2fish/story/1468339-tame-your-fishing-line-filler-spools" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="1" rel="nofollow">filler spool</a> on the floor so the line comes off the spool the same way it goes on your reel. This will help prevent twist. Holding the line tight in one hand, start reeling the new line onto the reel. It is important to keep tension on the line as it goes on to make sure it is tight on the spool. Loose line will catch on itself and cause casting problems.</p><p>Don&#39;t put too much line on the reel. Fill the spool to about 1/8 inch of the lip. You may have to take the cover off to check as you spool it and if you do make sure you don&#39;t pinch the line when replacing it.</p>If you did not run the line through the rod guides before spooling new line, run it through the guides now and tie on your favorite lure and go fishing. When casting it is a good idea to hold the reel so you can pinch the line between your fingers and keep it tight as you reel in. This is most important when reeling in a light lure that does not put tension on the line. A crankbait or a fish pulling against the line will keep tension on it.If the line is twisted after you put it on, remove the twist. You can idle along in a boat and trail line behind you with nothing on it, then reel it in slowly. You can also lay the line out in your yard or house and slowly reel it back on the reel. There should not be anything on the end of the line when reeling it back on the reel.