Welcome to TheSwamp.
You will need to copy the first bit of code & paste it in a text editor.
Save the file to a folder in the ACAD path using the file name "Line type-load.lsp"
Copy the next bit of code or better yet use this below.
Same procedure but name it what ever you like.
Replace MyLtName with your line type name
Replace MyLtFileName with the file where the line type can be found. Must be in the ACAD path.
You may replace MyLtLoader with something you like.
Add this routine to your 'Startup Suite'
You can then type MyLtLoader at the command line to load the line type. Note that you must close & reopen
the drawing for the startup load to take affect.
(defun c:MyLtLoader()
(if (zerop (load "Linetype-load.lsp" 0))
(prompt "\nError-could not load \"Linetype-load.lsp\"")
(Linetype-load '(("MyLtName" "MyLtFileName") nil)
)
(princ)
)