You said you are trying to make a script and dont know where to start so why not write down what u are gonna do?
So a tanning script would probably need cowhides + coins. So why not start at the bank
1. Start script at bank check if inventory has hides + coins if not then withdraw them
2. If invent has hides + coins then walk to tanner and tan it
3. Now that the inventory has tanned hides go bank them
As for the methods i think they got updated? Im not too sure so the old ones might not work, but try and see if the line u suggested works.