How do I name GuiXT scripts and Input scripts?     

GuiXT scripts: GuiXT scripts are simple text files. They follow strict naming convention. GuiXT script names are based on the ABAP program name and four-digit screen number. A language is also included for various languages. Format: xxxxxxxxx.ldddd.txt ( xxxxxxx is the ABAP program name, l is the language and dddd is the screen number). For language independent GuiXT scripts ignore the language key.
Example:
For transaction MM01 first screen, the ABAP program name is SAPLMGMM and screen number is 60; the language is English. The GuiXT file name will be SAPLMGMM.E0060.txt
In normal practice please accept the name GuiXT and/or Script Editor Pro propose while saving the active screen.
Input scripts: Input scripts are simple text files as well. They do not have any restriction on what they can be named.
Example:
save_workorder.txt