Since you are 100 percent new to hex editing, I can help you out.
First make sure you patched Alttp correctly, so that PW 1.1 works! You need to patch the IPS to US headered rom, this is the US rom with 1.025 KB. Once you've successfully loaded PW in the emulator, you are good to go.
This is how hex works: 00, 01, 02, 03, 04, 05, 06, 07, 08, 09, 0A, 0B, 0C, 0D, 0E, 0F, 10, 11 etc.
As you can see, there are 16 bytes (not 10 like in decimal system) before reaching 10. In the hex editor you have only even hex values on the left.
Lets start at the beginning:
1) the header is a sequence of 512 bytes (in decimal), this is 200 in hex, at the very beginning of the file (those are mostly 00 bytes!). PW has those bytes by default. Those bytes would mess up your address calculations (they will shift them for 32 lines down). That's why you need to erase them. Open the rom in the HxD editor and select the 512 bytes (200 in hex) at the beginning (those are mostly 00 bytes!), press Del and save.
The file should start like so: 78 9C 00 42 9C 0C 42 9C 0B 42 9C 40 21 9C 41 21. This must be in the very first line.
2) Where is 9C6 (if header is removed)
"Go to 9C6= 00009C6", means go to offset on the left 00009C0 (this is the row), while going on the beginning of byte 06 in this row (since there is 00 to 0F bytes in one row). You can also select: edit-go to, and type in 9C6, and the program will auto jump to this address.
Now copy this from txt
A6 13 DA A2 80 8E 00 21 86 13 20 A1 92 FA 86 13 60
then go to address 9C6 and press ctrl+B = paste-overwrite!, NOT ctrl+V (this will paste-insert and extend the rom, which will Destroy the file).
As you can see this sequence has 17 bytes, which is (11) long, so it is one row and one byte long.
3) in this case go to row BE0, and on byte 03 in the row. You should see these values there: A1 92. (the 92 is obviously on BE4). So now change this to C6 89, so that the former value A1 becomes C6 and the former 92 becomes 89. You can do this manually (no copy pasting needed).
When you are at the beginning of byte A1, just type C6 and it will be overwritten.
With this explanation, I think you can manage it now.