*Help* Merlin Pro v2.43

I'm having trouble using Merlin Pro 2.43:
-The Manual I printed is for a slighly different version of Merlin
-The cursor editing is slighly different between the two versions.
-From the editor assembler, each line is numbered by the editor. 1,2,3,4,ect
-From the ":" Prompt pressing ESC changes the cursor to "+"
-At this point I can use the cursor keys to move upwards and edit a line above

QUESTION: How do I save the changes made to a line of code?
(Pressing Carriage Return Doesn't Seem To Do It)

Any Help is much appreciated, and as a new Apple IIe Platinum owner, my story is below

I just bought an Apple IIe Platinum off eBay about a week ago,
I pieced the whole system together,
(the computer, the 5.25 drives, the drive card, a super serial card, an 80 col expansion card, and a colour monitor)
And it came to less than $200 including shipping.

Its my first Apple (not including my Iphone)

I had an Atari 800xl as a kid but I could never get my hands on the cartrige needed to do assembly on it. Recently I read the story of how Steve Wozniak created the Apple i, and ii computers basiclly by himself, which really impressed me. And once I found out that the mini assembler was BUILT INTO ROM, I knew I needed to get my hands on this thing!

I got the DB25 to RS232 cable, and I've got ADTPro working, so my access to software is unlimited!

Will